Short somewhere in electrical system

[Ryan S.]

Whenever it feels like it, but usually after a few bumps in the road: Voltmeter drops way below 12, dash lights dim and/or get much brighter (choke light does not), stereo goes dead, side markers flicker. Have not noticed headlights dimming or flickering. All this began with the mysterious flash in the back of the truck, which I think is the reverse lamps coming on. For awhile only the flash would happen without all the other trouble.

I have looked everywhere that I could see wires/connections. Eliminated or fixed a few suspect things, but still the short is there. Recently had a trailer brake controller installed, but the install is very clean. However, the short made itself known a few days after the install of the controller. I am at a loss here. The only thing I can think of is that the short is inside one of the devices-dash light dimmer, head light switch?
Any ideas?

 

[sebo4wd]

What if you tried removing the brake controller and then see if your problem still exist? If thats not it reinstall the controller. Good luck.

 

[lovetoski]

Whenever it feels like it, but usually after a few bumps in the road: Voltmeter drops way below 12, dash lights dim and/or get much brighter (choke light does not), stereo goes dead, side markers flicker. Have not noticed headlights dimming or flickering. All this began with the mysterious flash in the back of the truck, which I think is the reverse lamps coming on. For awhile only the flash would happen without all the other trouble.

I have looked everywhere that I could see wires/connections. Eliminated or fixed a few suspect things, but still the short is there. Recently had a trailer brake controller installed, but the install is very clean. However, the short made itself known a few days after the install of the controller. I am at a loss here. The only thing I can think of is that the short is inside one of the devices-dash light dimmer, head light switch?
Any ideas?

The reverse light switch is underneath the truck, on the tranny. Might want to look there to see if there's something obvious wrong with the switch. Might just disconnect the switch too to see if that makes a difference.

Try yanking some fuses. If the problem is gone, then it's in a circut that's been disabled. Reinstall one fuse at a time, until the problem reappears. That circut is where to focus your energy.

Could the flash of light be the rear cargo light? Maybe something is loose inside it?

Bumps causing the trouble could mean a loose connection somewhere too. Stuff gets loose in an old truck.

 

[Ryan S.]

Before I went and tore into more stuff, I took a look at the brake controller wiring diagram and it has power in, power to the trailer brakes, brake light, and a ground. By the process of elimination, I think that the short is isolated to the lights, at least that was the case while driving home from work yesterday. This morning I thought that I would try to isolate it even more by only having the parking light/dash lights on. Nothing happened. Turned on headlights. No short at all this morning. Apparently the 60 didn't feel like shorting out today, but I think that I am closing in on it.