When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Now the alternator dilemma is solved, it's vacuum pump noise!
I have the dreaded "only blows thru defroster" situation going on. I checked the pump today, and it's runs constantly. I turn on the key, and it sits there and buzzes. I m guessing it's shot. The truck has 160K miles on it.
I ve never heard it make any sort of noise before till this morning.
Is there a procedure for checking this out, or does the situation warrant another pump, considering it's constant state of activity.
You know that they suck when they are good and SUCK when they go bad.
The pump may be good.
Pull the line off it and plug it and see if it stops running
after a bit. You need to do that till you find the leak or a bad pump.
You can rent one of the little hand ones with a gauge at most parts
stores and with that you can track down leaks.
Thanks for the info,Yahiko! I blocked off the main line coming off the pump and it did shut off immeadiatly, so I m searching for the leak..wife is complaining about no heat on the floor.
I found the diagrams on this website helpful. I searched till I was crosseyed for a vacuum diagram for my truck last night and finally found these this morning!
At first, I thought it was the canister. After some trial and error diagnosis, I have concluded that it is,indeed, the ESOF relay. I bypassed it ( I have manual lockout hubs), plus I eliminated the canister. The only thing hooked up to the pump is the heater control system. The heater controls work fine, tho I didn't try the AC yet.
I do have one question since I bypassed the ESOF relay thing: Is the transfer case actuation vacuum operated like the hubs were? If so, I ll be needing to get another vacuum relay.