I have an old horse trailer that doesn't seem to get power to the brake lights. Is there a way to check that the connnector on my truck is actually putting out power?
I realize that the likely culprit is the plug on the trailer(it is somewhat corroded) but I would also like to eliminate the possibility that the problem may be with my truck.

 

You could hook to a known good trailer. You could have someone test it with a multimeter. If 4-prong you could go to walmart or elsewhere and buy a 4-pin tester for $5.

I have 4 and 7pin testers I have with me always.

 

A 12 volt test light will work for you. Cheap and you will find a use for it later in life. I use mine a lot on problems like this.

 

X2. I forgot about test light, good call.

 

Tekonsha 6562 7-Way Blade Tester and Trailer Emulator with LED Display