Intermittent weak grounding

[Kevbz]

Occasionally, when I go to start the truck it will loose ground to everything on the accessory, or hot on key, which includes the starter. I lose radio, chime buzzer, starter, gauges...but have constant power, head and taillights, dome and horn

I can go weeks and no issues, then it might loose ground for hours, or days. Last night it was me working on my door panel, I hit the power lock switch and it locked, but immediately lost ground. Went out 45 minutes later and turned the key and everything was back. It seems to happen whenever there is a quick large draw on the truck, like hitting the power lock, or horn.

I've gone over all the big grounds, battery to frame, battery to cab, battery to core support, engine to cab ect.

I'm down to starter solenoid, which I doubt because it can happen without ever trying to start it. Ignition switch maybe, or ignition module, if there is such a thing? But once again, can happen with out even having the key on. Maybe fuse block ground? Bigger cab to battery grounds?

I'm at a loss, the symptoms of when and how long it last are the baffling part.

 

[Shorty81]

Welcome from the Buckeye State

 

[Charlie]

 

[Doppleganger]

Do they all share the same ground? Seems unlikely but dunno. I've had similar past issues on other vehicles and it was usually the switch. Can you wiggle the key (cw-ccw) and get it to do it?

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[dvdswan]

Check your grounds inside the cab. Just because the ground is tight, that doesn't mean its good. You need to take off the ground and clean the bolt, connector, and connection point. A little di-electric grease will help keep it clean for a long time.

 

[Snoots]

Engine to frame?

 

[Kevbz]

Do they all share the same ground? Seems unlikely but dunno. I've had similar past issues on other vehicles and it was usually the switch. Can you wiggle the key (cw-ccw) and get it to do it?

No amount of wiggling, jiggling will get it to work. I've reached up underneath the dash and moved everything and tried it.

It had an aftermarket alarm on it and i thought the alarm brain was bad, which would kill the ignition circuit...but i have completely removed the alarm and it is back to factory wiring

 

[rt66paul]

Are you sure the positive is tight?

 

[MikeB]

Are you sure the positive is tight?

Yeah, why are you thinking grounds are the problem? Have you checked for 12 volts on the fuse panel when the problem occurs? If it is a ground problem, try using outer star washers behind ground straps from block and/or frame to firewall.

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You may also want to unplug the firewall connector and clean the contacts. My 82 had two 10 gauge (metric equivalent) wires feeding the fuse panel, but I had so many intermittent electrical problems and low voltages to headlights, etc, that I replaced the entire wiring harness, I now have nearly 14 volts to the HEI distributor and headlights. (Insert non-existent "thumbs up" smiley icon here.)

 

[gotyourgoat]

 

[Kevbz]

Yeah, why are you thinking grounds are the problem? Have you checked for 12 volts on the fuse panel when the problem occurs? If it is a ground problem, try using outer star washers behind ground straps from block and/or frame to firewall.

You must be registered for see images

You may also want to unplug the firewall connector and clean the contacts. My 82 had two 10 gauge (metric equivalent) wires feeding the fuse panel, but I had so many intermittent electrical problems and low voltages to headlights, etc, that I replaced the entire wiring harness, I now have nearly 14 volts to the HEI distributor and headlights. (Insert non-existent "thumbs up" smiley icon here.)

I am assuming it is loosing ground because I still have power to the constant power circuit, so the battery terminals are good and power is flowing to the fuse box. Trying to "deduct" what it could be leads me to the ignition circuit is losing ground, assuming that it makes ground contact when you turn the key to power the ignition on. I loose all accessory power, so its a bigger ground than just the ignition switch. Maybe the starter relay? I dont know, just guessing at this point

 

[Rusty Nail]

It's all about the purple wire!