Blown fuse

[Jimamatic]

I hooked up my travel trailer yesterday and noticed the battery power was very low, almost
dead in fact. Checked the charger fuse under the
hood and sure enough, it's blown. Is this a common
thing, or do I have a problem with the charging
system? My trailer has two batteries. Could they
be bad? The fuse just melted but did not blow,
indicating an over draw and not a short. Any
ideas?

[Tom Ellis]

Jimamatic,
How are the batteries in the travel trailer hooked to the truck fuse? Are they a direct connection? or do they go through a relay or diode.
It sounds like they are a direct connection and when you connected the trailer and started your truck, it tried to use the trailer batteries to start your truck, that would melt the fuse.
Another senerio, if the battreies are hooked up through a ddiode or relay, would be that the trailer batteries are low and trying to pull a lot of current from the truck charging circuit, melting the fuse.
:eek:
Tom

[Jimamatic]

Tom,
Thanks for the info. I think it's a direct connection to the batt from the truck. Sounds
logical. Going on another trip today. I'll try
starting first then plug in to see if that works.

Jim.

[HowieE]

Hi Jimamatic

Were is this charging fuse? What amperage? Is it in the alternater to battery circuit or in the battery to trailer circuit? Generaly GM uses fusable links in the heaver circuits.
If it is in the battery to trailer circuit I agree a low truck battery may have drawn enough current to melt any fuse in that circuit. If however the fuse was in the trucks alternater to battery circuit it should not have seen the cranking amperage.

What year is your truck? the 90s have a serious problem with the parking light circuit when towing a trailer with more than 1 or 2 parking lights. They melt the wires just at the switch and cause the head light switch to fail. Relay your trailer parking lights off your trailer batteries to eliminate this problem and save the $54.00 for a new switch.