Ac problems.

[ben774]

I've been chasing ac problems. On my new truck it is a 2000 7.3l crew cab 4x4 with the dash button. Ac is blowing out of defrosters. I don't have a lot of time money or the right tools to be messing around with the vacuum lines. But I replaced my vacuum pump because that seems to be the culprit for most people. Well that $75 piece of plastic did nothing.

I turn the key to the on position and I hear or feel no motor running on the vacuum pump. So I tested for voltage at the orange plug on the vacuum pump and I have none. I checked the fuse and it is fine. Where do I start?

 

[Arisley]

You have a vacuum line running from the pump, down to the front hubs. There is a leak there somewhere. Remove those lines and plug the pump. Bet everything works. Find and repair the leaking vacuum lines.

 

[ben774]

Did you read I'm getting no voltage at all to my pump? It would be electrical not vacuum right?

 

[Arisley]

Oops, missed that.

Is there power at the fuse?

 

[Derkperk]

Chill Benny.
Is there power at the fuse? Through the fuse? Must be the wire inbetween the fuse and pump.

 

[ben774]

Thanks for the fast replies guys. Do you know what fuse that would be?

 

[Arisley]

I turn the key to the on position and I hear or feel no motor running on the vacuum pump. So I tested for voltage at the orange plug on the vacuum pump and I have none. I checked the fuse and it is fine. Where do I start?

I thought you checked the fuse, and it was fine? Just pull the fuse and check for 12V.

 

[Derkperk]

:whs:
Hmm. Check the owners manual.

 

[ben774]

Fuse number 28 was blown I replaced and still not working.

 

[TERRCO]

Maybe re-title the thread to vacuum pump problem. Have you checked all the maxi fuses?


Sent from my Nuclear iPhone

 

[Arisley]

Is there 12 volts at the fuse. If not, trace backwards until you find it. If there is, then trace backwards from the pump until you find it. Or trace forward from the fuse until you lose it.

 

[TARM]

Also just because you may have found one issue does not mean there could not be more than one. If you have not I would still take the 5 mins to pull and plug the lines going to the front hubs just so they are taken out of the equation. Then you can trouble shoot the rest. I agree with checking to be sure you have 12V at the output side of the fuse box. Then check it at the pump again. From there you need to work back from the pump looking at the wire and see if you have a break or short some where. The fact you had a blown fuse might indicate you have a short somewhere in the line.

 

[ben774]

Okay weird thing happened. I fired up the truck the pump wasn't running. With the truck still on I unplugged it, plugged it back in and the pump started running. I the pump continuously ran but I had AC finally!! I blocked the lines coming from hubs and that stopped it. I checked with a vacuum pump only the drivers side Hub is leaking. It is not the hose. I can hear air escaping from behind the Hub I think?