Hey, I'm having one hell of a nightmare wiring this mess of a car.

Here's what's happened:

The car was poorly taken care of, and apparently there were a few shorts in the wiring harness. I ordered a gauge cluster from aliga, and I think it was a bit newer than my '92, because it has the AT gear indicator lights in it, which my stock one didn't have.

I got: new plugs with pigtails from a 92 SC400 (I have an SC300), and all the wires match up.

i rewired every single wire in the harness, and tested for ground and power where it should be.

Here's the dilemma:

Every single wire that i've checked has checked out fine, and the ones which weren't, I just spliced from a good power/ground source and fixed the issue.

The cluster backlights do not light up at all, though the CEL/oil/brake/abs lights light up fine, and as far as I can tell, the tach and gas gauges work fine. (although tach is a bit high, anyone know how to remedy this?)

Also, the turn signal lights dim greatly when i turn on the turn signals, but on the opposite side (i.e. left turn signal starts blinking when I indicate right)

When I turn on the lights, the odometer dims until you can't see it anymore.

All the fuses are good.

I'm stumped, and I need to know if there are any extra grounds/powers I'm missing, cause as far as I know, everything checks out.

I also need to know if pin 12 on harness C is a power or a ground, cause for me, it's a ground, and the wiring diagram shows otherwise.

I don't think it's an issue with the board, because I have another board that looks identical (sc300), and the issue remained when I switched the board.

I would really appreciate any help on this matter, it's been bothering me for the past 3 days.

Thanks,
-Freddy

 

Using the diagrams from my gallery? I think we have spoken about them before. It seems you have a diagram from what you are saying so I assume you are. I've verified them.

PS- any cluster will crossover and WORK below 97 so it is not the cluster.

 

yes, i'm using those. pin 12 on harness C is a ground for me, but on the diagram, it looks like a power.

I'm stumped.

 

i had similiar problems like what you mentioned. for me it was 2 loose grounds located behind the stereo. the grounds are held in with 10mm bolts and there should 2 of them. they screw in on top of the transmission module. hopefully this works for you, cause it worked for me.

 

Those are tightened down, and I even sanded down the contacts.

Are there any other grounds I should be aware of?

 

there are also 2 grounds, one on each side near the shifter, i believe. i had a similar problem when i didn't bolt those down...

 

any pics of these?

 

Nope, but if I remember correctly, when you take out the center console, you'll see 2 wiring harnesses running along each side by the shifter. There were 2 grounds around there.

 

There aren't any grounds by the shifter. By the way, the entire car's taken apart, and I see where there are mounting points for grounds, but I don't see any points on the harness. I'll try to peel back some of the electrical tape i put on there. By the way, I did a 5spd swap and eliminated the auto shifter and harness.

It's also weird that every ground that i've checked on the harness has continuity with the body.

anyone have an pics of these grounds, or diagrams?

Thanks.

 

i did a 6spd swaop and elimanted all the stuff you mentioned. everything still works for me. if you are positive the cluster is 100% working, then i would put money down on some type of missed ground. the symptoms you are having were almost identical to what i had. good luck!

 

I'm going to post up pictures and a diagram of everything I've done so far. I hope it's as simple as a missed ground, sure sounds like it, but I can't figure out where, since all the pins check out. Maybe it's a pin on the trip or rheostat?

 

these are the 2 bolts/grounds that i had missed.

btw, i had the problem on my 5sp sc3.

 

I'm pretty sure I have those 2 connected, I'll take pics and post the diagram tomorrow.

 

bump...anyone?

 

Here's the diagram and pinouts I made:

The ones I'm having an issue with are highlighted in bold.
Harness A (21 pin)

1-5 = Auto tranny (not used, i'm 5spd)
6 - X (not used)7 - seat belt
8 - fuel
9 - x
10 - airbag
11 - airbag pos (12v tested)
12 - open door
13 - parking brake
14 - charge pos (12v tested)
15 - charge
16 - A/T (not used)
17 - speed sensor
18 - O/D (not used)
19 - Oil
20 - Cruise (not used)
21 - X

Harness B (18 pin)

1 - Trac off (not used)
2 - x
3 - Check Engine light
4 - ECT (not used)
5 - Trac (not used)
6 - ground (tested)
7 - High beam
8 - oil level
9 - washer (not used)
10 - X
11 - rear light
12 - X
13 - X
14 - X
15 - ABS
16 - LH Turn
17 - RH Turn
18 - coolant

Harness C (23 pin)

1 - Power (12v tested)
2 - Rheostat
3 - Rheostat
4 - Rheostat
5 - Rheostat
6 - trip - Power (12v tested)
7 - fuel
8 - fuel
9 - Tach signal
10 - Ground (tested)
11 - Power (tested)
12 - Power? Ground? It tested as a ground, with 40 ohm resistance.
13 - speed sensor
14 - speed sensor to ECU (tested 12v???)
15 - speed sensor
16 - Trip
17 - Trip
18 - Trip
19 - Trip
20 - Trip
21 - Water temp (not used)
22 - ground (tested)
23 - ECT (not used)

As you see, my problem is in interpreting the diagram that OLT has provided, i'll post them up in a bit. The main discrepancies are in harness C. I dont know what the values for the rheostat and trip plugs are and should be, and pin 12 remains a mystery on whether it is a ground or power.


If anyone can chime in, I'd be very grateful.

Thanks,
-Freddy