I'm really stuck on this one and could use some help. I had convinced myself it was the cluster solder issue, but now I'm not sure. It happened on and off a few times, but now it's permanent and the truck is inoperable. On battery, all electrical systems are dead: no lights, no gauges, no crank. The gauges wiggle a little at key on, but don't really move. Sometimes I will get a no bus error after 30-60 seconds. Fuel pump is not turning on at key on.

If I hook up a battery charger, lights come back on. Door open / key in chime sounds a little weird, like it's two tones at the same time, but any attempt to start makes the relay just buzz. If I turn on the flashers, that relay buzzes. I put a meter on the battery and I'm seeing voltage briefly drop from normal down to 7-8V every few seconds.

If I run the cluster test with charger connected, everything seems fine in terms of lights and gauge sweep. I get errors 920, 921, and 999. I pulled the cluster and squirted a bunch of contact cleaner in both sides of both connectors-- no change. I went ahead and disassembled the cluster to take a look at the solder joints, and they all look OK to me. One interesting thing is one corner of the odometer LCD looks a little scorched, but it seemed to work OK during the cluster test.

Other things I have tried:

• had battery tested (was fine)
• cleaned PCM connectors (PCM is only a couple of years old, BTW, but it was a reman part)
• completely disconnected radio (no change)
• swapped ASD relay with known good relay (no change)

Any advice on where to go next? See anything in the pics I'm missing? I kind of feel like I might have a short somewhere, maybe in the fuel pump, and that's what's making the voltage drop. I'm going to pull that relay tomorrow and see if that fixes the voltage fluctuations.

Thanks,
Matt

 

When you hook up the charger, where are you making the connections? Right at the battery terminals or using a body ground? It sounds like a dead battery but you've tested it. Therefore, I'm going with a bad electrical connection from one of the battery cables. Bad ground, broken wire, bad main fuse. I have seen battery terminals, the posts themselves, actually loose in the battery but the battery seems fine. Was your battery "load-tested?"

 

I had negative disconnected for some troubleshooting, so I hooked to positive on the battery and negative to the clamp which was just floating in air. Battery was tested at AutoZone (it's a Duralast Gold, about 3.5 years old). I do tend to agree with you on the battery-- that's why I had it tested first. Maybe I should just go ahead and replace the grounds to the battery clamp. Is there an effective test procedure or should I just swap them? I'm going to double check the main fuse and PDC connector to make sure it's tight tomorrow too.

Matt

 

I suppose you could just make some simple jumper wires with a few pieces of 12-14 gauge wire, tie them into a decent ground point on the truck...

 

Replaced the engine ground and both battery clamps, and I'm back in business! Thanks for steering me back there. Since they looked good I breezed over them, but obviously there was a hidden problem.

Matt