My truck does have A/C. And the strange thing is, it worked wonderfully all summer but lately has been cycling when the heat is on which I thought was strange. This is probably bad as well but I found a random piece of vacuum hose underneath the truck that's not attached to anything. I saw it and looked around for where it should be connected to but couldnt find a place that seemed to hook up to it. It's back farther near the transmission and I have no idea where it goes. I know that anything that looks like it goes somewhere but isn't attached is probably not good. Any ideas on this new mystery?

 

that hose is the trans overflow tube(most likely). it wouldn't cause any problems. and the a/c kicks on when the blower is set to defrost to keep the refrigerant flowing in the winter to prevent compressor locks and the like. And as far as the surging goes, check yer e-coil. I had (still have) a problem with my coil connectors vibrating out of place from time to time(lost the little gray keepers) and my lights go dim, my engine diesels, and it makes a popping/detonating sound. ....From a mechanic who is to occupied to work on his own truck...

 

if it's back near the trans, it'll be your vent tube, not an overflow tube.

make sure it's tied up near the top of the firewall (there should be a little plastic "hat" on it, it's the breather (stops crap from getting in).