Engine/Transmission (1998.5 - 2002) No 4x4 & my Vents are stuck on defrost

[klaybus]

Complete vac pump failure or perhaps a substantial vacuum leak? I'm thinking the latter due to a fuel filter change recently but..... What do you think guys?



Clay

 

[Bob4x4]

Most likely a vacuum leak. If you just changed the f filter there are a number of lines that connect near the w/strip that always falls off. If that is good check the line that drops down to the cruise servo,batt acid will eat it.

 

[klaybus]

Thats what I'm hoping for. Gonna check it out in the morning when I can see better. I took a quick look & everything appeared to be attached but somethings going on. I'm going to follow them ALL out tomorrow.



Thanks,

Clay

 

[blacksheepdiesel]

That vacuum pump is extremely robust, save for the seal on the steer pump shaft. My pump had 670,000 miles before the shaft wore enough it wouldn't seal properly, but it still had plenty of vacuum. I measured one once and at idle it was pulling 28 inches!!!

Godspeed,
Trent

 

[EdK]

Look there

Look below the seal along the top of the firewall for vacuum lines. My fat hands and elbows pulled one off a "t" fitting when changing the fuel filter and I had the same issues.



Ed

 

[klaybus]

Problem solved!

On the drivers side at the weatherstrip there's a vacuum tee. Somehow during the fuel filter change I pulled the plug off the end of the tee. Defroster\heater vents now function correctly as well as the cad operated 4wd.



Thanks guys!

Clay

 

[klaybus]

WTF? I got my 4x4 back & my hvac controls seemed to be working correctly but the blend doors don't appear to be functioning right! I've got NO defrost & in the Pacific NW iin wiinter, this is a must! Can anyone tell me on a 1999 if there are more than (2) vacuum line connections on the drivers side at the firewall?

This thing is kickin my *****!



Thanks,

Clay

 

[klaybus]

ttt please...

 

[Bob4x4]

The vacuum line to the hvac unit enters the cab near the heater hoses



Bob

 

[klaybus]

Bob... .

I just went out & found the following. Does this sound about right? All liines are intact & now my heater control functions are working correctly... Hmmm.



Thanks,

Clay



1) Line fromm Vac pump goes up to check valve at firewall

2) After check Valve line tee's & runs (1) vac line to Cruise servo then tee's &

3) Runs another line down to transfer case & then tee's & runs across firewall to heater core area & enters cab to supply vacuum for heater vents

 

[Bob4x4]

That sounds right. The funny thing is on your last hvac post,you said it would not go into defrost. Defrost is the default position,no vacuum = defrost



Bob

 

[klaybus]

That sounds right. The funny thing is on your last hvac post,you said it would not go into defrost. Defrost is the default position,no vacuum = defrost



Bob

I kknow. That's the weird thing... When I found the missing cap on the tee ALL I had was defrost with no functioning of my hvav controller. Yesterday afternoon I couldn't direct the air anywhere what so ever. Then later yesterday, everything was working fine. Getting ready to run to Starbucks & we'll see if their still working right this am.....



Clay