Hi, 06 blows through the defrost again. So i looked for lines that came unplugged, nothing. I unhooked line from reservoir and the pump quits but then turns on then off on then off and so on. Would this mean I have a leak, or need a new pump??

 

Unhooked it from the reservoir and plugged it with something? If it was just unplugged it shouldn't shut off as it has nothing to pull a Vacume against.

 

Rusty, I plugged it with my finger. There was suction, and then it shuts down I leave my finger on it, then starts up for a second then off then on...

 

Could it be leaking just a bit at your finger? If not it's leakin somewhere else. If you're somewhere very quiet you may be able to hear it.

 

Did you check the one that plugs into the a/c heater control valve? That vacume line sometimes comes lose and then falls down where it can't be seen. I had the same thing happen on my truck and my buddies. Took me a while to diagnose it the first time.

 

cg- I did check, and it is there and plugged in. A few days ago the line going down by the front tire was apart. Plugged that in then it worked fine. This weekend went up into the mountains and locked in the hubs, put it in 4wheel and ever since then it started blowing through the defrost.

 

Disconnect the vacume line to the 4 wheel drive solinoid and plug it with golf tees or something. See if your system builds vacume. It was a quick way for me to diagnose the problem was in the 4wd system. In my case it was the the 4wd solinoid itself that had failed and was leaking. I near went crazy looking for the problem.

 

Sorry for asking this but where is the 4 wheel drive solenoid?

 

No problem. Passenger side on the side of the engine compartment. I beleave it is above the vacuume pump. Has two vacuume lines pluged into it, they are joined togeather. One comes from the vacuum resivor and the other one goes to the front hubs. Remove and plug the lines. See if it fixes it. The problem is in the 4wd drive area most likely.

It is called a vacuume pulse solinoid.

 

Thank you, I will check today.

 

Well, I removed the lines and plugged them and the pump still runs. Any other suggestions?

 

this was my fix on my 2005 f350

 

The pump has two lines that loop back around and just one line going to the resivour. If you plug that line the pump should shut off quick and stay off. If it doesn't the pump is leaking somewhere. If it seems to be holding ok, disconnect the other lines from the resivour, I think there are three of them, and cap the nipples with plugs from the parts store, reconnect and run the pump to see if the resivour is leaking. If it is ok, plug the other lines back in one at a time until you find the culprit. You may need a short piece of 1/4 line to go between the pump and resivour for testing, the line from the pump is in a double plug I think.

 

Rusty, I only see one line going into the reservoir and one line coming out. Its a double plug. So, would I plug the hole in the reservoir that is coming out that goes to a t and then on to the hubs and inside the cab somewhere?
Sorry just a little confused.

 

In the hub itself is a vacuum seal could it be that a seal has gone bad? I had a simular situation and it turned out to be the seal.