jesusfrk77

So I have a 95 XJ that is a salvage(from previous owner) and I have been having weird electrical issues off and on(I think the weather may have something to do with). So sometimes when I get into my beast in the morning and turn on the defroster 2 seperate issues can occur on any given day.

Issue#1-blower only blows air(hot or cold) out of the defroster vent on dash, side vents and foot area all the time not matter where the selector on the control is at. I did swap old selector unit out for another used one from a wrecking yard(the high low switch broke on my original) and everything looked good on the repacement and switch seem to work good just can't get air to switch levels.

Issue#2-Some days when I first start vehicle I will go to turn on defroster or a/c and when I turn heat or a/c not only does it not come on but it shuts my radio off(which is very annoying cause I love my tunes) but I can't defrost windshield either. After a while of driving sometimes this issue goes away, and sometimes it doesn't. I do notice that anytime I turn on my air (heat or cold) the volt meter goes from 14 to 12 or lower.

I would greatly appraciate yalls help as I don't want to tear apart the entire dash only to find I still haven't found the problem, I am a little electrical savvy and have access to Alldata for this vehicle but it has been no help. One wierd thing I've noticed is that when I look up the fuseblock layout for this vehicle(one under the dash) it isn't correct for my specific vehicle as far as the fuse #'s.

jeepiah98

#1 I have the same problem on my Jeep, but after about 20 seconds it finally switches over. My defrost airflow is horrible though no matter what. That's going to be an issue with the winter coming!

#2 The blower thing, I think, is just a characteristic of our vehicles rather than a problem. For some reason having the air go from "3" to "4" (full) sucks up a lot of juice. This was the case for my current XJ and my last (a 97).

Troth

Yep, Sounds about rite. Your XJ fits the aging criteria... Youre rite on Track !!!

jeepiah98

Any way to increase the throughput for the window defroster though? I'll deal with an aging Jeep, but i'm in New England... the ice is comin'! lol

Troth

phew, youre looking at heater core, possible radiator and coolant systems... I just put up with it. it sucks when theres 3" of ice/snow though

jjstultz

Sounds like poor vacuum to the actuator that opens and closes the flap between heat and ac. There are two locations ive read about on the forum that can cause this. The first is the vacuum feed line that runs along the passenger fender. Jeep engineers thought it would be a good idea to route this line under the battery. Guess what happens to that plastic line when battery acid gets on it. The second issue is the vacuum canister cracks. I believe most XJs have them located behind the front bumper on the passenger side. Its made of plastic and will get brittle with age. If these aren't your cause i would verify you dont have a leak anywhere else. Hope this helps.

jesusfrk77

Thanks for the help fellas and especially JJ. I've been thinking that it's a vacuum problem as well, I will just have to follow every vacuum line I guess and try to track the leak down. I went to go to work this morning and imagine that the defroster wouldn't come on again until about 5 minutes or more after starting vehicle(usually I jump in and go), may have to start vehicle 5-10 minutes before I leave and just put up with wasting a little gas.

jjstultz

Sounds like poor vacuum to the actuator that opens and closes the flap between heat and ac. There are two locations ive read about on the forum that can cause this. The first is the vacuum feed line that runs along the passenger fender. Jeep engineers thought it would be a good idea to route this line under the battery. Guess what happens to that plastic line when battery acid gets on it. The second issue is the vacuum canister cracks. I believe most XJs have them located behind the front bumper on the passenger side. Its made of plastic and will get brittle with age. If these aren't your cause i would verify you dont have a leak anywhere else. Hope this helps.

jjstultz

Any update on this

VTJeep

he is? cause id say its a vacuum issue... its so common. ALSO! a simple heater core flush (and backflush!!) are all you need to get that heat working, which isnt the issue at all (so an odd choice of info to give...) if there is little, no, or irradic airflow to any vents, the first thing that i would look at is the vac leak. mine will switch to the defrost vents when on the throttle enough to keep speed up a hill, or when taking off from a stop. you can try just unplugging a vac line off the manifold and cover it to see if it makes a diference. kinda a trial and error method, but it may give you some new info to work with. your radio short is probably a bad ground or a bad relay. do some searching for more specific info on where to look for certain relays.. idk... good luck! i hear ya with the weather! im in the NE area and winter dont **** around here!

jeepiah98

Thanks, I'll give it a shot!
What would I expect when I disconnect the vacuum line though? More/Less heat?

cpnwrench

well, do you by chance have a little silver thingy (vacuum switch) located on the passenger floorwell just underneath the dash near where the vent doors are? if so, see if that actully moves when you change from defrost to heat...if it don't try getting another one from junk yard and see what happens. I know on mine I have a small orange tube going to it, this comes from the heater control mechanism located in the dash ( the one with the levers and dial ****). on the back of that mechanism are other color coded small vacuum tubes, blue, white , and I think yellow and a green one too....these control the doors via that silver thing I described earlier....at least on my jeep anyway.... check all those and see if they are plugged in good.....also there is a cable attached to the control mechanism ( a bowden cable i think its called), this also controls the door movement within the dash environmental control ducting.....if you have the mechanism out, you should hear one of the doors move when you move this cable ( retract, extend motion)....if not, then either the piece holding the cable to the mechanism is broke, or where its attached to one of the vent doors, or the cable itself is bad.

just my experience sir, your mileage and frustration and ********* may vary (at minus 10, yeah it varies!)


good luck sir!

cpnwrench