Mismatch between electrical diagram, fuse identifiers and my car

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10-02-2018, 02:46 PM
nkemp

Mismatch between electrical diagram, fuse identifiers and my car

I thought I had a brake light problem ... but the problem was that my car does not match the wiring diagram(s) which does not match the fuse diagram/legend. And I'm sure the PO did not rewire the car.

The diagrams show the brakes powered via an always on power source via fuse #18 (my #18 is empty ... and I have VIN 897 so supposedly there is an inline fuse which probably isn't there (or I cannot find it or it is too late for the inline fuse )). Instead my brake lights are powered through a ignition switch activated relay and fuse #4. Most fuse panel diagrams show that #4 includes the "directional indicator and stop Switch" and #18 as the "stop lamps". Since there is no indicator that the brake lights (stop lamps?) go through a relay, this just seems wrong.

Supposedly the turn signals are fused by #6 per the wiring diagram and not #4 as indicated in the fuse legend. I've not checked that one yet.

That begs the question of what circuits are protected by what fuses and what other discrepancies there are.

So if you are doing some electrical chasing channel a bit of Pirates of the Caribbean " ... the code is more what you'd call "guidelines" than actual rules" Or in the DeLorean world "The wiring diagram is more what you'd call "guidelines" than actual wiring representation".

An aside ... it is amusing how the loads are distributed amongst the fuses. Really ... a fuse that appears to only protect the reverse lights.

That's my frustration vent for today.:mad:
10-02-2018, 06:01 PM
Ron

1 Attachment(s)

I'm guessing yours is like several I've seen:
Attachment 58169

(Directional "indicator" may/not mean "lamp"/"lights" on different schematics/charts, which sux ....)

The brake/stop lamp fuse was inline, located near the brake pedal (Green wire...maybe a stripe?) and was hot all times on this D. (Many are.)
10-02-2018, 09:55 PM
nkemp

Quote:

Originally Posted by Ron

...The brake/stop lamp fuse was inline, located near the brake pedal (Green wire...maybe a stripe?)

On mine, the wires from/to the brake switch go to the harness within about 6 inches (and I doubt there is a inline fuse buried farther in the harness). And when I pull the #4 fuse, I lose brake lights.
10-03-2018, 03:11 PM
dn010

I've found the wiring to be different between very early vins compared to others. I am sure your front wiring harness that goes to the fuel pump and radiator etc. is also different from the diagram. I had some wiring from vin 712 and it did not match my car 5003.
10-03-2018, 06:21 PM
Patrick C

There is an extra set of wires by the brake light switch in 1880. Those wires are only powered when the key is turned. The other set of wires are always live and are what I have hooked up to the brake light switch. There is also a nylon fuse holder with a glass fuse that powers those always-live brake light switch wires down under the dash in 1880. This is all factory. I would guess your VIN is the same way.
10-03-2018, 11:08 PM
Ron

Quote:

Originally Posted by nkemp

On mine, the wires from/to the brake switch go to the harness within about 6 inches (and I doubt there is a inline fuse buried farther in the harness). And when I pull the #4 fuse, I lose brake lights.

Yeah, JimJam's is like that.

Quote:

Originally Posted by Patrick C

There is an extra set of wires by the brake light switch in 1880. Those wires are only powered when the key is turned. The other set of wires are always live and are what I have hooked up to the brake light switch. There is also a nylon fuse holder with a glass fuse that powers those always-live brake light switch wires down under the dash in 1880. This is all factory. I would guess your VIN is the same way.

1669 was like 1880 ie had both.

A while back Dennis and I came up with 3 or 4 different harnesses, iirc.
There was one that had an extra TTS plug (WR & UB wires) near the firewall.