All Kinds Of Vacuum Problems

9

9jhester

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Feb 2, 2009
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414
I have been searching over the last couple days and aint come up with much.

Heres the problem:

Air/Heat only blows out the defrost
4x4 lights is on in 2wd and goes off when you put it in 4wd

I have chased down every vacuum line in the truck, and all are attached and have not found any leaks. Just wanted to see if anyone had these problems before and if they were related in any way.

Thanks, Hester
 
As for the 4wd light, sounds like the vacuum lines are crossed at either the axle or the cross member connections.

The air vents go straight to the defrost vents when there is no vacuum in the system. This usually is a result from a broken line. The line running across the bottom of the cowl to the passenger side and running into the fire wall at the heater core and a/c box is the line for the vents. Check it out again. Nothing else, bring it by the shop tomorrow and I'll check it out.
 
Alright, ill check it out some this afternoon a little more if i cant figure something out ill holler at ya. Thanks Bragg
 
I had the same problem when I did some work on the driver side of the motor. Accidently disconnected my main supply at the vacuum pump and forgot to reconnect it... Did yours just come out of nowhere or were you working on the engine recently?
 
It hasnt worked right since i had the engine out. I have ran over ever line 50 times and every connection is in and tight, i guess i could have maybe hit a line or something and caused it to leak i will look again here in a little bit and maybe see if i can find a pin hole in one of the lines.
 
displacedtexan said:
The AC problem can also be the actuator... Under the dash on the drivers side.
Click to expand...

But the fact that its 4wd and the HVAC makes me think its just a vacuum supply. Do you have cruise control still? Cruise, HVAC, and 4wd are the 3 things that require vacuum on these trucks. Good way to tell of you have a main supply problem or another problem all together.
 
Red Sleeper said:
But the fact that its 4wd and the HVAC makes me think its just a vacuum supply. Do you have cruise control still? Cruise, HVAC, and 4wd are the 3 things that require vacuum on these trucks. Good way to tell of you have a main supply problem or another problem all together.
Click to expand...

I agree.

A few weeks back I lost a vacuum line that took out 4x4 and the arm got knocked off the actuator. Freak happening I know, but I figure I can't be the only one with crappy luck:hehe:
 
well i got the 4wd figured out and still dont have controls to the air. what do i need to look for now? i checked all the way across the line that runs over the motor and into the passenger side and didnt see any problems at all. is there a way to check the actuator your talking about?
 
I see where the actuator is. Well i found two of them but one has a yellow line and the other has red. is the anyway of seeing if they have vacuum to them? thanks again
 
I'd pull the line to it (yellow on my 97) an see if I feel it. Engine running of course:D
 
Alright i will check that and get back on here later. So im starting to guess that if i dont have vaccum there i got a problem in the dash somewhere??
 
ive gotta buddy who has the same problem on his 96.. no 4wd.. abs and ebrake lights are on.. defrost only no vents...he says hes checked over all the lines and found nothing... tried to offer to take him all brand new lines from my trucks.. but he turned that down...oh well... i hope u find out whats wrong!.. cause it sure is annoying... had it happen to my old 97.. but found out i had two lines crossed...
 
I have had it for about 9 months and its no fun. i still got some checking to do ( didnt get much done today because the wind was blowing like crazy and very cold) but tommorow im gonna try and see if im getting vacuum to the actuator if not i guess im pullin the dash :nail:
 
i had about 30 in. of vacuum when i checked my truck last year. wouldn't hurt to check and see if you even have vacuum. i tested it because i was curious how much it had. jaw dropped when i saw 30. gas engines usually are 15-20 in. at idle.
 
Well finally did some more lookin around at the vacuum lines and I found a hole in the line entering the cab on the passenger side. Evidently the line rested on the canister on the firewall and it burn a small hole on the bottom side
 
i have looked at every inch up and down side lol got busy this weekend and didnt get around to doing much i should get around to working on it today ill post on here later if i figure it out. Thanks once again!
 
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