No ignition power

[84K5offroad]

I was driving down the road and the volt meter jumped to 18.6, the vehicle back fired and died. Now I have no power to the windows, door locks, ignition, or radio. It doesn’t even try to turn over. Batteries are good, I removed the fusible links from the starter and nothing. Pulled the ignition module and there’s no power going to it. Now I’m lost and I have no idea. Anyone have any suggest?

 

[chengny]

I was driving down the road and the volt meter jumped to 18.6, the vehicle back fired and died. Now I have no power to the windows, door locks, ignition, or radio. It doesn’t even try to turn over. Batteries are good, I removed the fusible links from the starter and nothing. Pulled the ignition module and there’s no power going to it. Now I’m lost and I have no idea. Anyone have any suggest?

Have you checked the fusible link up near the junction block mounted to the FW. I would do that next. In addition to those components you mention that link also feeds a lot of other things via the ignition switch.

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[Charlie]

 

[84K5offroad]

Yes I checked that and both sides have power.


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[Cuba]

I would check ignition switch on the column make sure you have power to it... or the interior fuse box, but only some fuses will have power unless key is on, engine off. Even then not all all will have power, but most should. That would tell ya if ignition switch is somewhat working.
If not, start looking towards switch

 

[84K5offroad]

I have no power going to the ignition switch. I pull it last night and tested it.


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[Cuba]

So now it's time to look at schematics and see where it gets its power from.

https://www.gmsquarebody.com/threads/1973-1991-wiring-manuals.14498/

Might be at the main bulkhead connector.

 

[chengny]

Might be at the main bulkhead connector.

X2

Your connector won't look exactly like this (87), but the stab connections for the power feeds will be in the same bays as shown. Top row - most inboard bay and 4th row down - middle bay:

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h

 

[84K5offroad]

There’s no picture


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[Cuba]

X2

Your connector won't look exactly like this (87), but the stab connections for the power feeds will be in the same bays as shown. Top row - most inboard bay and 4th row down - middle bay:

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h

Wow, that's an odd spot for failure. How about that!

 

[Cuba]

There’s no picture


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On chengny's post. I see both. Maybe use browser instead. Tapatalk sucks, IMO

 

[chengny]

There’s no picture


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How about these:

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[84K5offroad]

Mine look clean.


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[Cuba]

So refer to the schematic link I posted. Print out the ones you need because I think it makes it easier to read, and you can write on them, checking off what & where you checked

 

[chengny]

Mine look clean.


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Don't go by how they look. Check for power with a meter. The probe should be able push through the black gunk, fit into the gap and make contact with the crimped connection. If not, pierce the red leads with the probe - as close to the block as possible. Electrical wiring generally fails at the terminations. You should always see battery voltage.

Assuming you still have headlights, tail lights, horn & dome light - correct? Here is the diagram for the circuits supplied by the RED 2 lead that transits the bulkhead connection block in the upper inboard bay. Unfortunately it is becoming apparent that it isn't the one you're having a problem with. The branch that serves the two ignition switch terminals (BAT2 & BAT3) is the lower one - 4th row down middle bay.

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