12 volt lights not working.

[camper 2010]

I have a 2010 Keystone Cougar, 27RLS. When I an on 120 volt shore power the 12 volt lights will work. When I try running the lights off the battery, which is new and test good, I can run only one light. If I turn on another 12 volt light all will go off. There is a relay next to the battery that may be the problem. Can anyone tell me how this relay should work? It acts like it kicks off and does not reset till I connect the 120 volts.

[JRTJH]

That "relay" is probably a 30 amp autoreset circuit breaker. My guess is that you've either got corrosion on the battery terminals, a loose connection or the battery is weak and won't hold a charge. Disconnect the battery, Check the water level, hook the battery up to a separate battery charger then after a few hours of charging, reconnect it and see if you have lights. Another option, if you have a spare battery (from a boat, or ???) replace the current battery and see what happens.

[SAABDOCTOR]

HI What is the voltage across the posts of the battery? then go to the terminals on the battery should be the same if there is no corrossion or a bad ground. just tryin to save battery swapping if the voltage is ok go in turn a light on and check again. if it drops a lot you got a bad battery (cheap load test)corrosion builds resistance but current will not go up because of it. if all checks out and you can get a hold of ampmeter that will read 30 amps. disconect one battery cable and put the meter in line. have someone trun on a light and look at the cuurent draw. then turn on a second light if the meter did not go up to 30 amps the dang relay is no good. two bulbs (incadesant) should only draw 2amps or less. most people equate resistance to high current. but if a batt is sitting with out cables on it the resistance accross the terminals is infinity and there is no current/ amps, short the batt with a wrench and the resistance is 0 and the current goes through the roof. happy hunting

[camper 2010]

This is a new battery, just had it tested again, no problem. No corrosion anywhere. The relay trips anytime any two lights are one at one time. 3 amps draw was the highest. I found a new relay on ebay for 6.95 + 1.95 shipping. I should know in a week if that was it. Thanks everyone.

[SAABDOCTOR]

cool beans!! i bet you'll be fine. i am crazy but i like electrical problems... as long as there not mine