Electrical Question

[aclay]

I went out to my TT this past weekend (we keep it at a storage unit) and the electrical system was dead. I thought I had the shut off set, but it's possible that it trickle drained. I plugged in the tow cable to my running truck to see if I could get something to light up, but not even the indicator panel (tanks etc) lit up. I left it hooked up for about 10-15 min and nothing, I tried tanks and a few of the interior lights. I checked the breaker panel and everything looked ok (I did reset them).

So thoughts on what the problem is? Is 10 min on the truck enough to get a light to come on? I have two batteries, they are about 2 years old. Could they be dead (as in need to be replaced)? I don't have a way to plug into mains until I take it somewhere.

[rrev]

Like i was saying, my dad thought so too. He'd been pulling his trailer for 7 years till he checked it

[aclay]

Thanks for all the ideas. I'm familiar with test equipment, I just wasn't sure how far my troubleshooting might have to go. I will look at a number of these when I go out there next time. The truck has been hooked up to the trailer before, so I know that the connections worked at one time, the TT has been sitting for several months without any power (or attention). One other small point is that I happened to have my Yukon XL, not my 3500 that day, but I have towed another RV with the Yukon, so that receptacle had worked at one time too. I'd never try to tow the 311 with my Yukon, but I figured the power system should be able to light something up.

This is a great community to ask questions!

[rrev]

GM's sre notorious for not having the power wire for your trailer plug not hooked up from the factory. In fact my dad's Duramax came not hooked up. He never new it was unhooked till his batteries weren't charged once and he called me for help troubleshooting. And his truck was 7 years old at the time. I'd check that first. Your trailer tail lights are powered differently that the trailer power wire.

[no2tracks]

Maybe the plug connectors between the truck and tt are corroded or oxidized enough not make a good connection. I know from experience. A good blasting with a cleaner could solve it.

[CavemanCharlie]

jc1843 wrote:
Many of the GM trucks were shipped with a "Dummy" fuse in the place for a real fuse, and looks like a real fuse. Look in the under hood fuse box-- usually Post 1 is the power to the trailer.

Yes, mine had the dummy fuse and it had to e replaced with a real one.

[jc1843]

Many of the GM trucks were shipped with a "Dummy" fuse in the place for a real fuse, and looks like a real fuse. Look in the under hood fuse box-- usually Post 1 is the power to the trailer.

[enblethen]

When I said check the lights, I meant the trailer lights when plugged into truck. There is a fuse that provides power to the trailer connector to provide power to the trailer.
If properly wired the circuit breaker on the tongue of the trailer should not be in the circuit when plugged into truck. If tripped it would not allow the battery to charge or provide power to the rig.
The main(battery)fuse in the 12 volt DC power distribution panel would prevent anything inside the rig from working.

[downtheroad]

2112 wrote:

There should be a main self resetting fuse in-line with the battery. Check that as well.

This would be my bet also...

[westend]

I'd suggest to take a side trip to a Home Depot, a Sears store, or anywhere else they sell inexpensive meters and buy one. First thing to check would be the voltage of the batteries. Without knowing the state of the batteries, you will get a thousand ideas on what went wrong and most of them will be incorrect.

If you've never used a meter, it's simple. Set the meter's selector to DC voltage, place one probe on the battery's positive post and the other probe on the negative post. Report back with findings.

[2112]

Without a voltmeter you are shooting in the dark.
There should be a main self resetting fuse in-line with the battery. Check that as well.

[ScottG]

Make sure the RV battery isn't shorted internally before connecting your truck to them.

[Jframpey]

Just to eliminate everything else I'd connect to the truck via jumper cables for 15 minutes while idling... You may not have any voltage on the 12 volt lead in the trailer hookup for several reasons, bad connections, or it may have never been hooked up! Using jumper cables eliminates all of them.

[aclay]

I did flip the cut off switch a few times just to make sure, and that didn't help. I did not check the battery connections within the box, that's a good tip. The truck lights worked, I'm pretty confident that wasn't the issue but good point.

[enblethen]

I would start by making sure the truck has 12 volts DC at the trailer connector. The lights should have shown almost immediately in the trailer.
Did you try the turn signals, taillights or brake lights? None of these working could indicate a ground issue.