Midget Wiring Project

[Loren]

I've been collecting parts, now it's time to start planning the project!

I took my first stab at it tonight. It really helped that I had a document to start from. Alex bought a Midget sometime last spring, and seemed to really love it, I figured he'd keep it (he didn't). But, when he started talking about wiring... I figured I'd run through the wiring diagram and break it down for him. What the main circuits are, how they're fused (and more importantly NOT fused), the wire colors for each main circuit, etc. This document made it a LOT easier for me to plan what I wanted to do. Half the work was already done!

I've got an 80A battery isolation relay that I'm going to use for main power. Every bit of power other than the one wire to switch it (and a branch off of that for "always on" radio power) will go through this relay!

From there, I'm going to a 12V Bus Bar that everything else will connect to. Almost anything of consequence is going through a relay.

I have a 6 fuse block, of which I'm only using 5, all on what was "main circuits" before:
Brown - dash lights, hazard lights, switching relays - was previously not fused at all and supplied almost everything in the car. Some of it was fused AFTER running through switches under the dash... but UNFUSED before that.
Purple - Interior lights
Green - Signal Lights
Red - Left Marker Lights
Red - Right Marker Lights

I have a complete headlight harness (really cool OE Toyota part made to upgrade sealed beam lights to H3 style) that includes fuses and relays for the headlights.

I have a 6 relay block, none of this was on relays before, and each relay is individually fused:
Heater Fan
Brake Lights
Marker Lights (this feeds the other two fuses)
Cooling Fan (future use)
Fuel Pump & Ignition Coil
Horn

All of this will require VERY little cutting and splicing. Almost all of the connections are at the existing fuse block, or nearby under the hood!

I'm still going to try to break it down into steps so that I don't have to accomplish it all at once.

[Loren]

Okay, I've got "the plan" mostly sorted. Danged if I haven't found uses for all 6 of the fuses in my fuse block, AND all 6 of the fused relay circuits, PLUS a complete headlight wiring harness that includes 2 more relays and fuses! But, it should cover all the bases. And in a pretty tidy fashion, if I do say so.

The first pic is of my first draft "brainstorm" page, and my second draft "this is how I'm going to lay it out" page. I'm going to try to redo that drawing digitally so that I can keep it for future reference.

This is my CAD (cardboard aided design) mock-up of the fuse panel. The fuse block at the top is the OE one. The one I'll actually be using has 6 blade fuses, it's currently installed in the car.

This is pretty much how it will be laid out, but I've ordered a couple of 6-slot terminal strips to make for easier connections. I'll use one strip for the "switch" side of the relays, and the other for the "switched" side. The terminal strips have screw terminals. So, I'll use ring terminals on the relay side (the harness coming out of the black box in the middle), and then I bought some tabs to convert the screw terminals to spade connectors for the other side. That'll make it easy to connect to the factory wires without having to disturb most of it by cutting wires shorter and fitting new ends. I can also use either fork or ring terminals wherever I want to.

The panel may need to be made slightly wider at the top to put those strips on either side of the fuse block. Or, I might lay it out with the relay box turned sideways and put the terminals on either side of it. That might make the panel longer. This is why I'm mocking it all up in cardboard... gotta see what's actually going to fit in the car!

So, right now, I'm waiting for parts. Should be here Friday or so.

I like how this is all coming together. The panel should be able to be mostly set up "on the bench" such that only the main power and ground connections will need to be "hard-wired" to the car. Everything else will be snap-in spade connectors to rigidly mounted terminals. Easy-peasy, and neat.

[Loren]

They layout changed quite a bit, but I somehow managed to keep it on that 6x9" footprint.

Here's the latest. I just test fit it in the car before I start fabbing the panel tomorrow. It fits well. Had to move the fuel pump... But it was only secured with a zip tie. Yeah, I'm gonna fix that, too!

I like how the layout ended up. Those terminal strips will make the wiring a lot easier and neater. The white wires are the relay triggers coming from switches in the car. The yellow wires are the switched relay outputs going to the loads in the car. The fuse block will get supply wires on one side, loads in the other. All of the car wires hook up on the outside of the connection blocks, so nothing crosses over anything else. Easy to see, no "rats nest" of wires.

Should be able to cut the plate (1/8" aluminum) and start drilling and tapping holes to put it all together tomorrow. Fun little project if you plan it properly!

Aside from fabrication and assembly and a couple more wires, the only part I'm missing (besides the brake light switch) is a mess of little ring-terminal-to-spade-connector adapters to go on the terminal strips. Those are due in Monday.

Brake switch is due today, it's in Ybor City.

[Native]

Lookin good.

[Loren]

Had to yell at Cathy today for trying to capitalize on all of my weekend time. Gardening is HER hobby, not mine! I don't mind helping, but I got my own shit to do!

I had two "stupid" moments today.

First one was with the new brake switch, which arrived today. Nice Japanese-made switch. It's nearly too long. And it's 10mm thread. So, I set out to re-thread it to 3/8-24. I bought a complete standard tap & die kit recently for just such an occasion. Tapered the end on the grinding wheel so that I could start the die, clamped it in the vice and got started. A couple threads in, I realized that I forgot to remove the 10mm nut! Oops. Well, it ain't goin' anywhere now! The new switch has a lot more threaded shaft than the old one, so the extra nut is not in the way. It can stay there.

The other stupid moment... I decided that it was time to cut the aluminum plate to mount all the relay and fuse gear to. I remembered that I'd designed it to 6 x 9". I marked that up on my aluminum scrap, and almost just cut it to that. But, then I decided to measure the mock-up just to be sure. And, sure enough, I'd made the mock-up 1/2" longer. It's 9.5 x 6". No problem, I've not cut it yet, I'll just move a line and make it 1/2" more. (see where this is going yet?) So, I did that. And I cut it out. Cleaned up the edges so as to not cut myself on it. Then measured it. 9 x 6.5". Fuck.

I opted to just roll with it. There's a little bit of wiggle room in the design, and I'd considered making it 6.5 or 7" wide before. I just hung the main relay and breaker off of the front edge by 1/4", it all worked out. Got all the holes drilled and tapped. Holes for the rubber feet. Hole for the one mounting screw. Was going to do two mounting screws, but decided to move the whole panel further away from the firewall to make it easier to hook up wires... that puts the other mounting screw hole just out from under the panel. So, one mounting screw. I may put a spacer under it to give it something to tighten against without stressing the panel. Build in a little compression of the rubber feet, it'll stay put.

So... stupid stuff aside...

The brake switch is in, but I'm not thrilled with the lack of clearance. I may pull it back off and trim the threaded end of the switch (and the plunger) to make it like 1/8" shorter. Yes, that would make a difference. Otherwise, it works. And if I fuck it up... I'll just put an OE switch in it. I now understand why they used that oddball switch design. Nothing else will fit! (the car was originally designed to use a pressure switch in a brake line for the brake lights, this was a production change at some point)

Midget New Brake Switch.jpg (349.83 KiB) Viewed 8298 times

The panel is almost ready. Need to round the corners and clean it up. Maybe paint it black. Need to make some brackets to hole the relay box in place. Otherwise, the mechanical part of this job is done.

Midget Bare Circuit Panel.jpg (1.36 MiB) Viewed 8298 times

Wiring will actually be easy once the panel is pre-wired and installed.

- Most of it will be OE wires that are present and in the right place... probably long enough to reach.
- Brake switch wires need to be extended... did that today.
- Horn will need to be grounded at the horns, and a wire for the horn button needs to be run. (that can be done later, whenever I decide I want to make the horn work)
- Heater fan wires need to be extended.
- Main power switch needs to be run to the dash.
- Main power wire needs to be run from the starter solenoid.
- Ground wire needs to be run to the panel.
- Headlight harness needs to be run. (that can and will be done later, I want to get the car back to operational status, can upgrade headlights later)

[AScoda]

[quote="Loren" Maybe paint it black. [/quote]
Maybe paint it red.

[Loren]

I haven't matched the car color yet. I have satin black Rustoleum on the shelf.

Opted to leave the main panel bare aluminum. Because aluminum.

Tonight, I fabbed the brackets to hold the relay box to the panel. Those are steel, and I just painted them black.

I'm off tomorrow. So, hopefully, I can get this all together and take the car for a drive!

[AScoda]

[AScoda]

dang, so large

[Loren]

Well, the Stones were like the biggest thing this side of the Beatles.

Got my power panel installed today! All seems to be working well, though not quite finished.

Was going to take the car for a drive tonight, even put the new wiper blades on cuz it's raining. But, when I went to back out of the garage, the brakes were having none of it! The car would barely move. My brake light switch... can't adjust it out any more due to clearance, is putting pressure on the brake pedal. Guess I'm back to finding a proper switch. Which is, ironically, where this wiring project began!

But, at least I've got it all back together and functional... and no smoke. And I'm all set for brake light relay, whichever switch I end up using!

So, the "short list" of things to do just to be able to call the wiring complete:
- run the wire to the dashboard for the main switch
- run a wire to the dashboard for the horn
- wire the horns
- extend heater fan wires so they can be controlled
- wire loom on all the new wires
- fix/replace/adjust the brake switch (again)
- install new LED headlights and complete headlight wiring harness (it's a plug & play kit, all I have to do is hook up power and run the wires)
- oh, and I need to look at the light wiring in the trunk. (I saw wire nuts back there... geez)

Until all of that is done and I've driven the car... the swaybar project is on the back burner. (it's not keeping the car from being driveable) And I've still got a ton of other things to do!

But, I'm making progress.

[Native]

No smoke is the best part.

[Loren]

Ran the 3 required wires under the dash today. I was moving really slowly, and got a late start, so didn't get very far.

One of those wires is the hot "always on" wire. It's FUSED now (was not fused in the OE wiring), and it only feeds the main power switch (to switch the main relay that powers EVERYTHING else), and radio power if needed to retain settings... assuming I ever put a proper radio in the car.

The other two wires are the one that goes to the main relay, and one that goes to the horn relay.

I put a bus terminal under the dash to connect the hot wire to. I just like the idea of having that point of connection. "This is the hot wire point, it's the ONLY hot wire point." Got that much done. Then I farted around trying to figure out where I want to put my main power switch... and what kind of bracket I'll have to make to attach it. Didn't come to any conclusions. Still trying to decide how much I want to take the dash apart.

My new brake switch arrived. It's not going to work. Way too fat. Length is good. But, it can't even be modified to fit. So, I took out the switch that I'd already re-threaded to fit. Shortened it by a half inch. Cleaned it up and installed it. Got the pedal box all back together, adjusted the switch and all is well with the brakes!

I even took the car for a little drive to celebrate.

[Loren]

Mmm... dusty in here.

So, "finishing up" this project morphed into rebuilding the console, as documented in another thread. That took care of the main power switch, the horn button, and a few other switches that I decided to add. Along with a new radio, new speakers, a USB port with a voltmeter, etc.

That's all done and functioning brilliantly so far!

All that's left of the wiring (that I intend to do... surely, there's more... there's always more):
- Heater Fan (just have to run the wires to the relay
- Headlights & Horn
- Cleaning up the wiring harness under the hood.
- Anything to do with the lights in the back of the car. (haven't touched that yet)
- Oh, and the fuel gauge is still flaky as hell.

I spent a good part of last weekend, and this evening, working on the headlight and horn wiring.

Really didn't need to do anything with the headlight wiring, that Toyota harness that I bought is complete. I did split a wire off of the high beam circuit to use to trigger my garage door remote. And, rather than futz with the OE horn wires... since I'm running that harness to the front of the car, anyway... I added a wire to that harness for the horns. That was the easy part.

In between researching how to add delay to my horns, and how to wire my garage door remote so that it triggers on the high beams, but doesn't stay ON and constantly transmitting anytime I'm running high beams... I found these cool little relay boards on Amazon. I could have built my own circuits, but this was WAY easier, and I got 5 of them for $12. What they do is delay switching on the relay that is on the board. There's an adjustable resistor to control the timing of the delay. They are standard relays with normally open and normally closed contacts, so the delay can either be a delay before turning something on, or a delay before turning something off.

For the garage door, I have the relay set to delay turning off by about a second. So, if I turn on the high beams, it will activate the remote for a second, then turn it off.

For the horns... what I wanted was "levels" of horn, but with one button. The initial button push is "friendly". So, you can give a little "beep-beep". It activates one horn, it's the more pleasant sounding one. If you hold the button for a second, the second horn comes in. Those two sound good together, they are a match set. Basically, the sound goes from an A note to a variant of an A Minor chord. The effect is Beee-EEEEP. And if you let it go again, you can get that as many times as you want. If you hold the button for 3 seconds, the obnoxiously loud horn kicks in. The combination of the three horns makes an F chord, but it's not at all pleasant. That's my "you didn't listen the first time" horn.

So, the relays allowed me to set all of that up. I bought a little plastic project box to put it all in. Had it done last night... or so I thought. I hadn't tested it with the actual horns.

Tested it this evening, and found that with the horns in the circuit, the relay for the second horn would chatter when it turned on. Sounded bad, and is bad for the relay. I went round and round with that. Re-did how I was doing the grounds, that didn't help. Replaced the relay module for that one horn, didn't make a difference. Tried putting a diode and a capacitor across the coil of the relay, no change.

Then, I finally hit on the correct search path that led me to the simple fact that horns are "electrically noisy". (the technical term is "back EMF"... EMF being electromotive force, which is a fancy term for "voltage") The way they operate is to make an break an electrical contact repeatedly to move a diaphragm and make sound. They're doing that with an electromagnetic coil. Similar to a relay, but a relay is using milliamps... a horn is using more like 6 amps! This charging and discharging of a coil kicks a reverse voltage spike back through the electrical system... and that's freaking out my relay control board.

The solution? One is just a diode across the terminals of the horn itself. It doesn't conduct when power is applied, so it doesn't act as a short across the battery. It DOES conduct when it sees that reverse voltage spike, and sends it straight to ground rather than back through the wiring. Hooked that up, and it seemed to work a lot better. Cathy was annoyed with me testing horns, so I only tested it once. I don't think it eliminated all of the chatter, but it seemed to reduce it to an acceptable level.

And with that: Horn and Headlight and Garage Door Opener wiring is tested and ready to install on the car! And I have tomorrow off.

[Loren]

These are the horns. A pair of Farbin brand cheap horns. (probably why they don't have any noise suppression) They are plenty loud, and the frequency output is pretty much as advertised. 410hz (actual 430, an A note) and 510hz (actual 512, a C note). I like them. For horns, they sound pretty good.

The red one is part of a Hella set. Much more expensive. Quite loud! But, they sound TERRIBLE. Nothing pleasant about them. Supposed to be 300 & 500hz. The 300 is more like 342 (an F note), and the 500 was 472. The 500hz horn sounded so bad that I opted to not use it. These two horns together... well, they are loud. Gawd awful obnoxious. Not what I'm after.

Here's the relay setup. One for the door remote, one for the C note horn, and one for the F note horn. I've got a roll of adhesive-backed weatherstripping foam that I've been using for lots of things. I stuck a strip on the back of each board, and also some on the inside of the box. This allows everything to fit snugly in the box without me having to futz with trying to engineer screws and brackets to hold it all together.

Here's the inside of the control box. With a little luck, I'll never ever see this again.

And here's the whole thing assembled. One ground wire. Blue wire from the high beams, Yellow wire from the main horn relay. Three horn out put wires, Yellow, Green and White.

[Loren]

Oh, I did a slight modification to the relay boards. The way I'm using them, the common side of the relay output is the same voltage that's used on the input side. So, rather than running an extra wire inside the box for each one (and it would require me to double-up with wires in the screw terminals), I soldered a jumper wire on the back of the board tying those two pins together. So, the yellow (and blue) wires coming in are 12V powering the module, switching the relay, AND also is the switched voltage that goes out either the NO or NC pin.

Also, FYI, I did modify the door remote. I did this LONG time ago, and don't remember exactly what part I used. But, it's a single-component voltage regulator that drops the 12V to 3V to power the remote. The main door button is also jumpered with a wire so that it's always active. When you apply power to it, it acts just as if you pressed the button.

[Loren]

Oh, and this is my latest wiring diagram. It's gone from being just the control panel with all the relays and fuses, to being that... plus the console... plus the headlight harness... plus the horn relay box. Heh.

I'm sure at some point in my life, I'll be glad that I documented all of this.

Midget Wiring - 13Feb2024.png

(193.89 KiB) Not downloaded yet

[Loren]

Started working on this today. This is supposed to be the easy part, right? All the planning and testing and wiring is done, just stick it in the car!

Nope. Well, realistically, I could have just slapped it together. But, the older I get, the more I want to take the time to do things right. And since I don't have to drive the car to work tomorrow, I have that luxury.

As I took apart the headlights to get to the plugs and replace the Halogen bulbs with the H4 housings and LED's, I was reminded of how awful that situation is. I mean, it's not "hopeless" or anything. But, the screws are a little rusty, the Philips heads are on the verge of being stripped. Somebody replaced the aim adjusting screws, but everything else is just... old. Including the gasket between the headlight "bucket" and the body. So, there's that.

And the really nice harness that came with my lights... the sockets won't fit through the holes in the body (or the headlight bucket) to install. So, the harness will have to be cut and splice.

Ditto, the old headlight harness. I need to get that plug out of the fender well so that it can connect to the new harness and give me switching. The old harness, OF COURSE, has been cut and spliced TWICE within 8". I imagine once when it was replaced (it's been replaced), and again when they did the paint work. And I wouldn't mind that, but BOTH of those splices are twist-and-tape. Geez.

Since I'm cutting the harness, I'm shortening parts of it. Several feet of excess wire. I've also decided to add plugs, one for each headlight "side harness" rather than just splice it back together. I ordered a pair of trailer light connectors to use for that. They are 4-wire, I only need 3. But, they'll be sufficient.

Ordered all new hardware (stainless) and the headlight gaskets so that I can put it all back together properly. And so, I wait.

The good news is that I got the horns installed and that all works well enough.

[Native]

Since I'm cutting the harness, I'm shortening parts of it. Several feet of excess wire.

Is that simplifying, or adding lightness?

[Loren]

Adding lightness, fer sure.