PDX_1ton

Here is a good one.
About 2 days ago the 86 1-ton started to intermittently no start as if the battery was dead, however all the dash lights came on and when turned the key to start, the whole system shorted out, as if the slow blow fuse went. After about 5 seconds everything came back on line. This issue would repeat. Then by magic it would start.

Until today,

Started doing the same thing, but it digressed quickly. Battery is good. Put key in to start, relays in center dash start to buzz. Attempt to turn over engine, entire electrical system shuts down and resets. Dash lights are starting to get dim. (Battery is still good)

Now when I step on the brake, dome light goes out, if the door is open.

Attempt a few things, un-hook radio/cd player. Relays under fuse box (driver side) start to buzz like angry bees if driver door is open. Now there is no dash lights at all. (I bought a new relay and it did not fix the problem)

Problem gets even worse. Now even with no key in at all, relay under fuse box buzz. If I attempt to turn over engine all sounds stop and there is a reset (no lights). If I turn on the running lights a new relay buzzes somewhere in the middle of the dash. If I turn on full lights, the Head relay next to the battery buzzes madly.

Any suggestions of either known issues or ideas how to diagnose (sp).

And I can't pull codes as there is no dash lights anymore. Battery is still good.

Thanks,
Christopher

PDX_1ton

Bump..

abecedarian

Relays "buzzing" is a sign of low voltage / excess resistance on the control circuit.
How did you determine the battery is good? With a rest voltage check? What's the battery voltage WHILE you're trying to start?

jtruck79

had this happen a few times and found that the body ground from battery was corroded. so first off clean battery cables loosen, clean and retighten, body ground. then pull clean and retighten body ground to engine mount.. dont forget to make sure the ground from firewall to valve cover is in place as well.. i would bet that if using jumper cables to start and you hooked up the ground to the block instead of the battery all those issues would quit. have fun make friends

PDX_1ton

Thanks Abe,
I'll check voltage with a meter in the morning. I was stuck in a parking lot with only borrowed tools. I'm crashing at a friends house tonight after we towed it here. Sounds like I have some grounds to take a look at in the morning.
(It seems you moved to TN. Last I knew you were in California)

Cb

abecedarian

I work on cell sites (adding antennae or other equipment to help your cell phone work or give new technology) so I travel where work is. I'm not living here, just visiting.

PDX_1ton

There is a short some where but I can not find it. I pulled out the battery, tested it and it was still at 12.85 volts. I tested the resistance on all ground leads and came out clear. I unclipped/unpluged a couple of the wire clips in the black box next to the battery mingled among a few fuses and tested resistance on the wires as best as I could.

I unplugged the ECU and reconnected it.

Couldn't find anything. Started to put everything back together an applied power to the system. The buzzing was no there and the truck started.

I don't yet, and it bothers me I don't know what the problem is. I'll write more if the truck dies again.

Christopher