Alternator charging WW batteries ?

[RidgeTop]

Anyone have any tips on checking whether my truck alternator is charging my trailer batteries?
Thanx,
Phil

[RidgeTop]

Anyone have any tips on checking whether my truck alternator is charging my trailer batteries?
Thanx,
Phil

[dieseldude]

All you need to do is measure the voltage across the battery when not connected to the TV, it will likely be 12- 12.6 vdc. Then measure it again this time with the TV running and connected to the Trailer, it should be about 13.5 vdc.

If the battery is bad, disconnect it completly and test the batterycables with the TV running and connected to the trailer to see if you have the 13.5 vdc if it is the alternator is charging. Just make sure you don't allow the positive cable touch the frame or other metal.


Hope this helps.

[RidgeTop]

Thanx for that Dieseldude. I found a extra red wire connected to the pos terminal with a 40 amp fusible link. I'm wondering if thats the cable charging the batteries off the alternator. Thanx Phil

[Y-Guy]

Many trucks, even with a tow package, require an additional fuse under the hood in order for the 7pin plug to charge your trailer. I had to have one in my Avalanche and F350.

[WWFan]

You know Y-Guy:

I seem to recall having to install the fuses myself (or the hitch installer) when we got both of our Fords- they came in the Towing Package Packet with a poopsheet on what all the connections where in the 7 pin connector.

[Disclaimer: That was a few 'moons' ago, and subsequently I seem to have lost the actual brain cells that held the detail].

[Y-Guy]

Yep same thing was supposed to happen on my Chevy, but they decided to save a few bucks on my Avalanche and didn't include it. I've been through the F350 and no fuse was there. Then again they also left off the hood blanket too.