cplev

Probably just a minor issue with installing some aftermarket fogs, but on using the old stock wiring to the fog lights on my 2008 JKU to provide a switched live to a relay(Bussmann fuse/relay box), the voltage appears low, around 11.5 volts checked with a meter, and won't trigger the relay. The relay does work and the new fogs come on OK with a direct wire from the battery triggering the relay, with a voltage of over 12v. Both stock foglight wires give the same low voltage.
Could the problem be 1) I haven't run the stock fog connection to earth direct from the old connector or 2) I'm testing with the engine off, and the voltage will rise when the engine is running? (I haven't been able to do this yet due to other ongoing maintenance.)
If addressing 1 and 2 don't solve the issue, is it possible to connect nearer to the actual switch on the stalk(I have to run some other cables into the dash for switched lives to other relays), or is there a feed direct from the stock fuse box I can wire into?

Any help appreciated!

Chris

Sixty4x4

Not sure why you did not replace the fogs with new and use same wiring with a load resistor if they are LED type. My guess is that the relay won't pull enough load in the fog circuit and the switching is done through electronics. Try a load resistor like 20W rated 25ohm across where the relay is connected so you are switching both. Assuming the stock fogs still work on the circuit. The resistor should pull about 0.5Amp when connected to fool the TIPM electronics.

cplev

Thanks for the reply. They are actually halogen fogs - I was wiring in some driving lights as well and thought I’d use the adjacent relay for the fogs in case the current draw was too high for the stock circuit - probably unnecessary as you say but anyhow. I will try the resistor as suggested - or try the original wiring! The project was started before LEDs were widely available at reasonable cost - tells you how long ago I started it!

Chris