Ive had this problem ever since I bought the truck, ive seen a TSB for it, but cant seem to find it...

When ever there is enough load on the engine, or thottle presure is high my heat / a/c switchs over to defrost mode, and then comes back to where ever i had it set.

If I remember right the TSB for this said to get a certain part number vaccum orfice and install it inline of a certain vaccum line.

Can someone lead me to this TSB or some info on this, becasue I would like to get it fixxed.

Thanks

 

I cant find the tsb you want with out more info . you can add a extra vac canister to solve the problem just about any size will do. theres just not enough vac under load. It's fed law that the hvac sys defaults to defrost if the sys breaks aka no vac. make sure you dont have a leak in the vac sys this will also have an effect on your cruise controll operation

 

do a search for 'wild vents' in the 2nd Gen forum

 

I just ate a couple of bean burritos so "Wild Vents" is really going to fit me in about 3 hours.