Len-Len

iTrader: (9)

So I got a short that makes my instrument cluster, idiot cluster, a/c, and reverse lights stay on with the key off. It also blows the fuse when I try and start the car. I know the cause is the black/yellow wire in the harness behind the dash. Its shorted somewhere but I dunno exactly where.

I took my dash out, unplugged the reverse light switch, and started checking resistances. The problem I'm having is when I cross check wires to see if they are shorted together, lets say one of the wires to the cooling fan, to the black/yellow wire, I come up with about 8 kilo-ohms. This happens when I cross check most of the wires in that harness to the black/yellow wire.

Logic tells me there's something I haven't unplugged yet. The circuit is not isolated yet and that's why I'm getting these high-*** resistance readings.

Question is, what haven't I unplugged yet? The car is an 86 base model, the ins. cluster, idiot cluster, a/c, alarm, reverse light, ign. switch, and cooling fan are all unplugged. According to the wiring diagram, that should be all that the b/y wire goes to for this model. I'd love to not pull that harness out the car because it looks like a bitch, but it looks like I have to in order to find this short.

Thanks in advance.

satch

iTrader: (1)

Cruise control, Alternator Warning Light relay/Warning/Seat belt timer.... in the CPU (largest plug houses the B/Y wire) and Auto Adjust suspension.

Len-Len

iTrader: (9)

Thanks for the reply Satch. Unfortunately the dash is out of the car and I already have the CPU connector unplugged, and this car doesn't have AAS.

I guess I'm gonna have to pull the harness out to find the short or just replace the whole shabangabang. That old *** harness is pretty hammered anyway.

Len-Len

iTrader: (9)

Haven't been able to work on this problem in quite some time. Got crackin' on it yesterday, still haven't found the short.

What I do know is the blue/red wire that powers the logicon, i/c, and idiot lights is getting 12 volts even with the key off. I am checking this wire underneath the dash, at the 2 pin connector that also has the green/white wire.

Everything is unplugged in the circuit. Dash is out, no cruise control or A.A.S in this car, instrument cluster, idiot lights, a/c, cooling fan, and CPU all unplugged. That little blue and red bastard still gets 12 volts.

Now correct me if I'm wrong, I checked the ign. switch by checking the large black/white wire. 0 volts. So the blue/red wire is not getting its 12 volts from the ign. switch. Also tried completely unplugging the ign. switch, stll twelve volts at the b/r wire.

Again, all components powered by the 7.5A meter fuse are on with the key off, and the fuse blows the minute the starter is turned over. I tried leaving the fuse out and putting it in after the vehicle is started and running, but it pops as soon as its inserted.

Does this mean the b/r wire is shorted to the charging circuit? Is there any place that the b/r CAN short to the charging circuit?

I'm stumped. Anyone have any input? Satch? Hailers?

satch

iTrader: (1)

The Blue/Red wire is probably powered by the 7.5 amp Room fuse which should have power 24/7 and is part of the battery buss fuses which receives voltage from the 60 amp BTN fuse in the engine fuse box so these fuses (battery buss) don't receive power from the ignition switch.

oinesra

iTrader: (2)

HAILERS2

See the jpg attached?

All fuses in the Blue area are on the battery buss and have power 24/7.

See the fuses in the Red/Orange/Yellow area of the fuse box? Those are only powered with the key ON or Acc.

So you have power on the Meter fuse with key OFF and that fuse falls in the Red area of the fuse box. This means to me that the wiring in the car is crossed up somewhere. As in some connector is connected to its wrong mating plug.

Say you have a elect plug with a wire in it that goes to the Batt buss and you mate that plug with the wrong connector and that wrong connector has a wire going back to the Red buss. What you have just accomplished is backfeeding power from the BAtt buss (Blue) to the IG1 buss (Red).

This means that now all the fuses on the Red buss have power on them 24/7. Not the way things should work at all.

Crossed alternator wiring will do this. Remove the small plug from the alt and see if now the items are still powered up with key OFF.

IF not that .............then we've had people misconnect connectors near the clutch pledal wrongly and cause this type problem. The cross a plug for the ignition switches lighing to some other plug............I foget which plug. It's a two wire plug. Anyway one plug is powered by the batt bus and the other by the IG1 buss.

On the jpg the batt buss is in Blue...............IG1 bus is in Red ........and IG2 and ACC are in ??? orange/yellow.

Prior to this problem............what kind of elect work did you do?? Alt change out? Reconnecting elect plugs around the clutch pedal/ignition key switch area?????? Or?

Len-Len

iTrader: (9)

Thanks fellas! Your info is going to help alot.

Hailers, the weird thing about this is it just happened one night. I did no prior electrical work at all, although its evident the previous owner did. I came home, parked the car, shut the key off, and the gauges just stayed on. I assumed it was a short because of this.

I have already tried unplugging the alternator as well as the starter (although I knew it wasn't going to help), still to no avail. A few of the lights in the idiot cluster turn off and thats is. I even pulled every fuse out aside from the meter fuse, still no avail.

Its a total mind ****. I went to the u-pull-it yard hoping the one FC they had would still have this harness in tact, but it was cut in several spots. I will try again tomorrow night and report back.

HAILERS2

If one of the two contacts inside the Main Relay stuck, that would also cause the problem. Pull both plugs off the Main Relay and see if that's so or not.

EDIT: I may have to rethink that one.

And or pull all the plugs off the ignitoin switch and see how it goes.

A radio miswire might result in the batt bus feeding the IG1 or IG2. I'd disconnect the plugs on the radio and see what happens.

IF you pull the METER fuse so the lights you mentioned go out? or not? You said you pulled all the other fuses other than the meter fuse and still had those lights with the key Off.

With all fuses in.........what happens to those lights you mentioed if the BTN fuse in the engine bay with key OFF?

Are the gauges registering with key OFF and those other lights ON?

I guess I should be asking myself why the meter fuse blows just because you start the car. Must be something pulling a lot of current when you do that. It almost sounds like the meter fuse is feeding a whole lot of other things other than those lights you mentioned.

I forget. Does the car keep runinng when the meter fuse blows?

Turn signals and wipers still work after the car starts up??? Matters.

Len-Len

iTrader: (9)

Update

Hailers, I did not realize that all things that are connected to the BTN fuse are things that have power with the ign. OFF. I wasn't reading the diagram correctly.

With the meter fuse in and the BTN fuse pulled, the gauges and everything turn off.

The b/y wire is shorted to the BTN circuit.

Thank you for clearing everything up Satch and Hailers. Now I just have to find where its actually shorted at.