1975 electrical adventures!

[707kevin]

i'm in process of removing all unnecesary wiring from the car. Normally I am a huge fan of un molested wiring with a strict 'no cutting' policy. This car isn't 'normally'! I thought I would share what I've found and removed.

I still can't tell what happened initally to cause the problems, but I found out today the EVERY wire through the the firewall has been cut at one point and soldered. Under the dash is a rats nest of wiring instead of loom. Most all connectors are original, but some fuses and relays are bypassed....

The fuel pump relay was bypassed. I found out why today. The oil pressure switch wasn't plugged in, so the pump relay never activated. I also found out why the oil pressure light cam on after driving a few minutes even thought the gauge reads 20-40 always. The oil pressure light was wired to the thermo switch under the intake manifold!! D'oh!

Turn signals. Previous owner cut the hazard switch harnes up. Never hooked power from hazard switch back to signal flasher! Easy fix. Also, flasher was bad and looked like it was pried open...just replace the thing they are 3.99 at the parts place.

Rad fan relay was bypassed. Plugs to radiator fan and coolant temp switch were cut. +12v was coming from a small wire from the engine harness and the wire showed signs of melting. The problem? Previous owner didn't know how to replace the faulty relay apperently. It's amazing how much effort goes in to doing it wrong, why is the first reaction to start cutting wires???

Because I desmogged, and the wiring is a bit of a mess, I spent a few hours to just pull out ALL the junk wires not being used. I used a pick to actually remove the spade connectors from the plastic connecter so I can put them back if needed or add new circuits easily. I haven't cut a single wire yet. So far I've removed...

cat temp module, relay, warning light, associated wiring.
Seat belt warning buzzer, indicator, and wiring
25k erg and cat indicator and wiring
Everything on connector 40 and 41 under glovebox came out.
All fast idle switches, wiring, relays (tranny in gear switch, test button, clutch switch, electro valve, vacuum lines, etc)
All diverted valve wiring and parts.
All ignition mode relay and wiring (runs single points now)
Key in buzzer and wiring

So many wires came off of connectors 37 and 38 that I ended up consolidating them to one connector and labeled it 37/38. The wire colors are all correct so future troubleshooting will no problem.

I'm leaving the parking break light and hazard indicator light, since they work and will look nice when I redo the dash wood.

All in all its a really easy electrical system to trace and troubleshoot. I'm amazed how hard of a time the other owners had with it.

I still need to rewire the ignition switch to clean up the wire nuts (as in home wiring!!) and poorly crimped spades. I'm down to just 4 relays in the car. Horn, rad fan, charge light, and fuel pump. All gauges work now and all gauge lights and indicators. Need to wire interior courtesy lights too. They are missing flexible LED strips worked awesome in the jeep, I still have a roll of that.

I'll get photos. I know others in the past have asked about some of this.

[tartan18]

Excellent write up. I did the same wire removal project on my 1975. The biggest challenge was to clean up the underdash wiring because a PO had spliced things together in several places with left over factory wires -- meaning that the wire colors had no relationship to the wiring diagram. That drove me nuts. The last issue is to get my horn working again.

[707kevin]

Yes, I don't fully unsderstand why previous owners all seem to be far below average intellegence.
I'm guessing there was a short at some point that melted wires and made a mess. Or and engine fire, since the pressed in fuel fittings on the 32adf seem to like to fall out after a while.

Under the dash is just a MESS. Rats nest of wires. The only way I will be ahppy is to take the dash out completely and re-loom the wiring and make a proper wiring harness and not just a bundle-o-wires.

[DieselSpider]

Same issue with the diesel conversion with all sort of taped up wires just hand twisted together. Still finding hot wires with no terminators hidden in various places. Everything I am doing is soldered with a spade or eye and all splices are Western Union Style (square knots with solder) all sealed with marine grade shrink tubing.

[707kevin]

The wires cut at the firewall are plain twists with solder, folded over and sort of wrapped with electrical tape. Before I put the dash back in, I'll install a weather pac style bulkhead connector, or at minimum western union solder and heat tube them