help please
 

91 chb my engine light comes on after about 10 to 15 min and my temp guage won't work and my fan won't come on what could be the problem i changed and tested the relays and they all work what else can i do.

have you checked the sensors ? there should be like 3 of them in the head

Get a Haynes manual if you don't have one. It should tell you how to get out why it's wrong. If not, I think you have to take it into the shop. Sry :no: .

the first thing I would check would be your colant temp sensor considering neither your fans come on or gauge works probally just a defective sensor could be wiring too get yourself a manual and multi meter set it to dcV and check to see if theres any voltage at the temp sensor you should see the voltage rise as the temp rises if its at around 5 volts when its cold you have a broken wire just thought I give you a few things to try if you have any more questions feel free to e-mail me and I'd be glad to help thanks ryan