Ok so I bought a 2001 ram 1500 about a month ago and im 16 so I don't know how to fix this but when you turn the lights on the cruise won't work hut when they are off the cruise works so if anyone can tell me how to fix that it would be great

 

Sounds like a wiring issue. Are you good at fixing wires? Or at least decent?

 

i don't know how to wire at all I've never done it before

 

When your headlights are on and you press the cruise on button does the cruise light come on in the cluster?

 

i don't think so but ik when you turn the lights on while in cruise control it just shuts off like its thinking the brake lights are on or something

 

ARE the brake lights on??

 

no that's the thing idk what someone did but i got it from my dads friend and idk who he got it from but someone redid some wiring and messed something up

 

Ready to learn about electrical?

You can download a service manual for your truck from here. Wiring diagrams are in section 8W. Have a look at the cruise control wiring, and see what changes when the headlights are on. That's gonna be a fun one though, as so far as I know, there is no overlap....... Cruise is controlled purely by the PCM. Turning on the headlights just shouldn't matter. I think looking at the brake switch first is a good idea though, as if that isn't wired properly, it could be your problem.

 

I think he has a bad ground and turning on the lights takes away the ground from the cruise control.

 

I would think if that were the case, the ground right up beside the drivers headlight would be a good place to have a look.