May be purchasing a Jimmy, had a few questions...

[jal1992]

Considering the purchase of a 2000 GMC jimmy with 145k on it... I know the man who owns it as of right now. It is mechanically sound all the way around but I have 2 main concerns...

1.) The heater only seems to blow air out of the defroster vent even though I have it put on floor.

2.) The sunroof does not open at all, I can hear the motor working, but the glass does not move.

Are these common issues that have any common solutions? Any help would be greatly appreciated. Thanks!

 

[Molson02536]

Considering the purchase of a 2000 GMC jimmy with 145k on it... I know the man who owns it as of right now. It is mechanically sound all the way around but I have 2 main concerns...

1.) The heater only seems to blow air out of the defroster vent even though I have it put on floor.

2.) The sunroof does not open at all, I can hear the motor working, but the glass does not move.

Are these common issues that have any common solutions? Any help would be greatly appreciated. Thanks!

The heater vent selection is caused by a Vacuum line to have crack or break in it. The lines from the engine to the vacuum reservoir and to the fire wall, go bad after a few years from the heat of the engine. After the vacuum lines are inspected and working fine, inspect for any fluid in the lines and also the switch on the dash.

If this is a 4x4 and you have fluid in your vacuum lines!!!!
What has happened is your transfer case vaccum switch is leaking. You now have transmission fluid in your vacuum lines and your hvac system. The first thing that happens is your vacuum pods that move the doors to change from vent to dash or floor fill up with transmission fluid. The switch will go bad, also the actuator for the front differential will go bad too and the vacuum canister will fill up with transmission fluid too.


The fix is to replace the switch and you need to unhook each vacuum hose and blow them out with air. Then you need to change out each vacuum pod if there damaged and can not be salvaged, you can get them from a junk yard to save on money. Make sure they come from a two wheel drive if you can so you know that they don't have fluid in them. Get a control switch too. Change them out and then you are good to go.

The transfer case vacuum switch is not hard to replace. You need a 7/8 deep well socket and a switch. Under the Jimmy on the drivers side and look on top of the transfer case, there will be three hoses that go to the switch that unplug. Just pull up on them to unplug, then remove the switch and install the new one and plug in the hoses. Just make sure your clean the area of where the switch is with brake parts cleaner to help keep any dirt from entering the transfer case.

Keep us posted and as for the sun roof, it sounds like the nylon gears are stripped.

Molson02536

 

[jal1992]

Thanks Molson. Any kind of vacuum diagram available or which ones specifically should I check? The one from the xfer case vacuum switch leads directly into the hvac and that's where I should be looking? The 4x4 works fine and the vents aren't smelly so I wouldn't suspect a problem there although I will definitely check the lines for fluid... I have a vacuum pump which should hopefully make this issue easier to diagnose and repair.

 

[Molson02536]

Thanks Molson. Any kind of vacuum diagram available or which ones specifically should I check? The one from the xfer case vacuum switch leads directly into the hvac and that's where I should be looking? The 4x4 works fine and the vents aren't smelly so I wouldn't suspect a problem there although I will definitely check the lines for fluid... I have a vacuum pump which should hopefully make this issue easier to diagnose and repair.

If you have a 4 button 4wd switch on the dash, you will not have the vacuum switch at the transfer case. The 3 button 4wd switch will have the vacuum switch at the transfer case.

The vacuum line comes from a check valve on the drives side by the pvc valve, the heat from the engine causes that part of the line to go bad from cracks. That's a good starting point and work your way from there.

The other known place for you to inspect after your ruled out that your vacuum lines are all good is the vent selection switch it self. The switch is just a multi vacuum valve which sends vacuum to the different actuater for the vent control.

Keep us posted.

Molson02536

 

[jal1992]

Ok well, after playing with it for a while. I got the vents to work from the defrost and the dash panel vents. I just cant get anything out of the floor! When I have the selector switch on floor vents it just comes out of the defroster!...

 

[2000redjimmy]

I have a 2000 jimmy with automatic everything. Ball joints upper and lower, wheel bearing have been a huge ongoing issue. The rear hatch and window in the hatch love to seize up so make sure you use them frequently and be prepared to jump in with a can of WD40 and elbow grease. The fuel pump and tranny has also been an issue. Presently I'm having a heating problem possibly related to the blower control module. If your HVAC has auto climate control, the vehicle will also have this VERY expensive module as opposed to the cheaper blower motor resistor. The rear wheel wells up top are very prone to rusting. I also had some power/voltage problems for headlights which was solved when I replaced the control arm on the steering wheel. It's our 2nd jimmy, but I think we're done after this one.

 

[barks507]

Sounds like your heat issue may be the actuator under the dash. Mine has a broken plastic hook which is suppose to connect to a metal arm that operates a door. I only get heat from defrost and vents. I couldn't figure out how to replace without taking dash off.

 

[2000redjimmy]

Thanks...I'd agree on the actuator idea, but my blower motor is not operating at all...it will if I jump directly to B+. Would appreciate any other suggestions though!!

 

[jal1992]

Thanks for the thoughts guys... I've moved on to a more pertinent issue now with my driver side brake light intermittently not working. I'm going to say it has something to do with the turn signal switch. Because the turn signals work fine and usually the brake lights only work right after using the turn signal.. I think it's the wiring in there but I've also heard of people having burnt wires under the abs unit causing the same issues...

 

[2000redjimmy]

There is often a brake switch under the dash where your brake pedal is connected it could be that. You should amuse yourself and change the bulb first...as weird as it sounds, it moght just be that. Oh...another lemon part on the Jimmys...had to replace that entire control arm that does the wipers, signals, four way, etc. If (when?) that time comes, there is an absolutely perfect how to on you tube by aaauto (or something like that). BTW, still no heat...still looking for troubleshooting on a automatic computer controlled climate system with a control module NOT the resistor. Thanks!

 

[jal1992]

I changed the bulbs already to no avail. I thin it is the multi function switch because I also noticed today that when I use my turn signal the daytime running lights shut off

 

[2000redjimmy]

could be...I replaced our multi switch about six months ago. Forget the link but there is an excellent step by step on you tube i believe be aauto.com or something like that...perfect instructions!