Mysterious No Dash Pod lights?? Tested Everything?

Mysterious No Dash Pod lights?? Tested Everything?

Postby Red86GT » Thu Jul 13, 2017 4:16 pm

86 GT 5 speed. I just fixed a no start no crank (and posted about it) because of a ground to short at the grounds in the back under the c500 block.

I had removed the gauge pod to get to the steering column to replace ignition components as part of the process. Got car running but when I put the gauge pod back on no gauge lights. Everything else works.

I see the check engine come on and off, the e-brake....I flip on lights I get parking lights, rear lights, head lights, turn signals, under dash lights, above head lights, chime and dingy etc..... just no main gauge lights, AC control lights or radio lights?

I read all the posts on pennocks, the archives, the cave etc. but nothing seems to give the answer to this mystery.

I have power to and from the dimmer and the test light will fade down when I dim the switch.I also swapped out another dimmer to test with same result.

Can the dimmer be jumped?

I have power to and from the transistor. I jumped it but still no gauge lights? I thought I should have full bright when jumping the transistor?

I know all the grounds are good because I literally check every single one on the car while resolving the no start no crank.

My printed circuit board is in good shape. No breaks on the visible surface. The legs or tabs in the connector slots are pretty good except the rt side vertical. I had to solder a few of those down but they been working great up to know.

I put a test light on the circuit board when the key was in the #2 position and had power on both sides of the lights that did light up.

The fuses test good as well.

My last resort is to replace the printed circuit board with one I have as a spare but really don't want to go thru all that if I am missing something small.

Any help is greatly appreciated and thank you ahead of time. It is 90 degrees in NC and I have been sweating like a sugared up fat kid at a cake party up under the dash and I am about to lose my sanity.
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Re: Mysterious No Dash Pod lights?? Tested Everything?

Postby Red86GT » Thu Jul 13, 2017 4:50 pm

**UPDATE**

I rechecked the fuses and realized when upside down I checked the wrong fuses.....sorry about that.

The two fuses I understand to be relative are the "gauges" and "instrument LP" ....they show no power?

Not sure how that is when I have power to the connectors?
Red86GT
 
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Re: Mysterious No Dash Pod lights?? Tested Everything?

Postby Red86GT » Thu Jul 13, 2017 5:07 pm

**UPDATE 2**

I put car in key position 2 or accessories. I got power to the 10amp "gauges" fuse. No light at gauges though....

No power to the "inst LP" 5 amp fuse?

Any thoughts? I still have power at the connectors and switches?
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Re: Mysterious No Dash Pod lights?? Tested Everything?

Postby Trinten » Thu Jul 13, 2017 5:43 pm

I'll see if CowsPatoot can check this thread out. He knows the stock wiring system pretty well. He's done some gremlin chasing in my car. Sorry it's being such a mind teaser.
1986 Pontiac Fiero GT, 355 cubic inch small block Chevy putting down 371 HP and 381 ft/lbs torque at the wheels, with more to come!
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Re: Mysterious No Dash Pod lights?? Tested Everything?

Postby Red86GT » Thu Jul 13, 2017 6:58 pm

Yea, it is when I jumped the transistor per the caves directions and got nothing that stumped me.

I have HL, TL..all lights inside and out, just no gauge lights?

It seems I have power going in and out everywhere but it is not getting to the gauge lights.

I am guessing it is gonna end up being the circuit board.

**Additional Info**

So been studying the diagram and all seems like it should be except no power to the 5 amp fuse anytime and nothing when I jump the transistor?

Image

With car on, every single fuse tests good, on both sides except the 5 amp INST LP

The curiosities is no power to the 5 amp fuse? It is not blown?

What does this mean?
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Re: Mysterious No Dash Pod lights?? Tested Everything?

Postby Red86GT » Thu Jul 13, 2017 10:17 pm

So I jumped the transistor again and then tested the fuse. I got power to one side so it is blown. I had never tested the fuse with the trans jumped so it just looked like it wasn't getting any power and visually it didn't look blown.

I put in a new 5amp then turned lights on. I heard a brief beep then fuse blew.

Apparently I have an issue after the trans on the way to the fuse box?

The only work done so far is clean grounds under c500 to get car to start again, new starter, new ICM, new coil, drop steering wheel and swap out the lock cylinder, put in a new ignition module, put steering wheel back on, remove dash pod, put dash pod back on.

The INST LP 5amp fuse also handles the headlamp warning? Will see if that is any part of it tomorrow.
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Re: Mysterious No Dash Pod lights?? Tested Everything?

Postby Red86GT » Fri Jul 14, 2017 12:05 pm

**UPDATE**..... with a question

I checked out the fuse box and all looks good from the front I am going to pull it off to look at back later.

I decide to do a continuity test on the printed circuit board before I pulled it off and swapped it and to maybe eliminate it as a source of the problem.

I did have one bad socket (which I changed out) but other than that I had continuity from pin/leg all the way thru the individual circuits across the whole board. All the bulbs tested good too.

So the circuit board has full continuity, the gauge pod goes back in, I plug up the transistor, try the gauge lights and nothing.

Then I jumped the transistor, tried the gauge lights and blew the fuse?

Could I have a short on the board and still have continuity? If no then the issue is some place else.

**Also I am posting this on Pennocks to get a collective view on the problem with as many approaches to it as I can get so maybe one is the answer**
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Re: Mysterious No Dash Pod lights?? Tested Everything?

Postby Red86GT » Fri Jul 14, 2017 2:42 pm

**UPDATE**.....Some progress.....a couple questions

Since the gauge pod and printed circuit seemed ok, I decided to take it out of the equation.

I put in a new fuse, left the transistor plugged in, gauge pod off and hit the lights while seeing if I could see any power to the connectors that plug into the back of the pod. No voltage or power to the grey wires......and no blown fuse.

Then I Jumped the transistor, hit the lights, blew the fuse..(without the gauge pod connected)...Not sure what this means? other than it is not the gauge pod?

To me this seems to at the least eliminate the pod and the printed circuit board as the problem. It seems to be an issue before the pod?

I do have an aftermarket radio in the car that has had no problems or caused any for the past couple years. I unhooked the radio checked all the wires all looks good.

QUESTIONS:

1-Is there a way to test the cables that plug into the pod for power to the grey wires etc? ....for voltage, continuity or anything?

2-Could it still be a switch?

3- Because the INST LP 5amp fuse also handles the "headlamp warning" and I do hear a beep when the fuse blows could it be something around that? Headlights come on and off, bright and
dim, go up and and down.

I do have a power on/ off switch wired up to the power wire that runs to the motors hooked up so I can cut the power off to the motors when the are not needed to raise or lower the
lights. It is just a simple interrupter switch to the flow of power though. It looks good with no shorting or damage to the wires.

Lastly as a recap of the order of things.....this all started after I took the pod off to replace components for the ignition on the steering column while resolving a no start no rank issue due to a bad ground under the C500. Got car running, put pod back on, no gauge pod lights but all other lights in and out function properly and I keep blowing the INST LP 5amp fuse.
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Re: Mysterious No Dash Pod lights?? Tested Everything?

Postby Red86GT » Fri Jul 14, 2017 8:29 pm

I was looking at the wiring diagram in the FSM (86 gt) for everything in either direction of the INST PL 5amp. On pg 877(PDF)....(8A 12-1 in the manual).

I am figuring I will just unplug everything connected to that fuse until I find the problem. Everything in one direction seems connected to the grey wire.

To eliminate that direction I unplugged the radio, the aux gauges, the AC/Heater and the audio alarm / convenience center, the only other thing I did not unplug was the trunk release. I am out of fuses so I will have to try it without the trunk release tomorrow when I get more 5amps.

*I moved the trunk release to a secret place so it is away from the dash pod which is why it was still connected.

If once I unplug all of the above listed things and the fuse keeps blowing does that mean the problem is in the other direction toward the switches? :?
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Re: Mysterious No Dash Pod lights?? Tested Everything?

Postby Red86GT » Sat Jul 15, 2017 2:16 pm

**DASH LIGHTS NOW WORKING!!**

The problem was two wires that were not supposed to be touching that were touching?

Going down the line in that direction from the fuse and removing all the components and eliminating them one by one worked to guide me to finding the problem.

I had moved by trunk release to a hidden area. There were two wires that were not needed. When moving everything to search for the short related to the no start no crank I had inadvertently rubbed them loose from where I had them secured and since they were so close they ended up touching....of course. My fault for not better securing them. :oops: :roll:

I separated them, secured them apart from each other, taped them up good and taped the up in a loom so that will never happen again.

The INST LP 5amp fuse related to the dash lights and them then going out can usually be easily solved by jumping the transistor or testing the wheel. My problem is sort of an anomaly due to previous sloppy wiring.

The most common dash lights issue out will be accompanied by you also losing your tail lights and is related to another fuse.
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Re: Mysterious No Dash Pod lights?? Tested Everything?

Postby Trinten » Mon Apr 02, 2018 6:36 pm

That's awesome that you found the problem. I'm glad that it was just causing a small short and stopping the lights from working, and didn't burn anything else out or cause a fire. This is good info! Thanks for sticking with putting in updates!
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