1988 4.0
the blower motor wont turn on checked the fuses under the dash.(OK)
what else should i check? i have the dash apart to replace the steering column so while im in there i would like to get it running,
also ac compressor wont engage.

 

I had a problem on my 90 like this except it would run for a while and cut off,come back on etc. I thought it was my switch but fond the connection closest to the motor under the hood was bad causing it to loose connection and heat up. I just cut out the connector and crimped the wires together and have had not more trouble with it
clint

 

that could have been it , i pulled apart all the conections i could find
and tried it again bingo it works lol and all the vac vents work as well.

but 2 problems left i dont get alot of heat out of the vents so i checked
the vac hose at the heater control valve and it has no vacuum

the other thing is the ac pump dont engage is there a relay for that?

 

I think the AC system on that jeep is completely empty, and if it is, I believe the compressor will not engage as a safety. So what did you have to do to get the jeep running?

 

Yes, what he said. If the clutch on the compressor won't engage there is a good chance the charge or freon is lost.
You can run a 12volt jumper and ground to the clutch and just see if it will engage to check the clutch but do not leave it on long as it might hurt the compressor.
clint

 

really not that much lol im really sure what was wrong but first i didnt hear the fuel pump running so i disconnected the fuel filter and shook it out looked ok so i turned the key (screw driver) and checked to see if the pump was any good (pumped fine) so i tried it again and it fired, sweet!

 

Cool man! Waiting for you to get that build thread up!

 

ive done alot to it already

 

Wow
Keep them coming! Get that build thread started!

 

i'm having a similar problem. my blower wasn't working when i bought my 88 xj, the po unhooked the elect. harness from the back while installing the new stereo. i hooked it back up, & it worked! (sorta) it would only blow out the defrost, but @ least it would blow hot! figured it was a vacuum prob. i opened the hood & fiddled w/ the vac lines, incl. the purple one that goes to the heater control valve. nothing worked until i moved the out/return line from the heater core to the thermo housing. i can hear a kind-of sucking (vac?) sound if i move the hose a certain way. i guess new heater hoses & hcv are in the near future? anyone got some lying around?

 

check to see if u get vac at the actuator door controllers on ether side
under the dash. just pull a hose off and see if u have vac. if not it could be a line came off. also check the back of the heater control unit to see if it came unplugged and check the vac canister at the bumper for cracks or broken lines. have fun

 

I have a similar issue with mine. The ac clutch kicks on for a second and then off with the relay in, but a jumper wire will make it run until it's unplugged. Also, my blower motor won't blow; has less than 1volt at the plug but works just fine when I took it out to test for a dead blower. Any known problem spots for corrosion or broken/breaking wires?