My stupid 1999 XJ need some help

89wrangler

89wrangler

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Joined
Oct 22, 2005
Location
Bostic,NC
Bought a while back thinking I could make me dd out of it, nothing fancy just 4x4 transportation. I should have checked it out a lot closer, but that is on me so here I am. Try to get the AC working now that fall is here. :shaking: Anyway, determined the evaporator coil was bad so I swapped it out, new accumulator, all new O rings, pulled vacuum and let it sit, no leaks. Went to charge system and the compressor will not come on. My question is there a way check compressor or jumper the pressure switch to get it kick on? Anything else to check? Thanks
 
I always disconnect the compressor clutch and check voltage at the connector if the clutch is suspect
 
should be able to bypass the low pressure switch and activate/check power at the clutch. I have also just ran a jumper right to the clutch from the battery to activate it for a test.
 
Ok, back to the top. I have checked the fuse and it is good, checked pressure switch and it is closed, unplugged hot wire to compressor and ran jumper to it and compressor kicked on and got cold air.
There is no power at the compressor plug. Does any know where the power for this comes from? The dash switch only has vacuum lines. Close, but yet so far. Thanks!
 
My 99 has a low psi switch n the freezer dryer, jump that connector and compressor will kick on.
 
There is a fuse underhood as well as an AC clutch relay. Power is supplied via the HVAC controller in the dash. Check fuses in the pass kick panel too. All of them. The PCM drops the ground for the AC clutch relay when it sees the request.
Make sure all of the connectors you removed are fully seated. Been there, done that.
Jumping across the low pressure switch should turn on the comp if the rest of the circuit is initact.
 
Checked every fuse visually and with test light inside and under hood. All good. Also made sure all connections were good as well. Put a jumper on the pressure switch again and still no power to compressor. Of all things I don’t have a spare relay, so I ordered one of those to try to rule that out. I don’t think that is it, but need to be positive.
They way it looks there has to be a pressure switch somewhere to activate the compressor since the dash switch have only vacuum lines on it? Thanks for the replies!
 
Last edited:
89wrangler said:
Checked every fuse visually and with test light inside and under hood. All good. Also made sure all connections were good as well. Put a jumper on the pressure switch again and still no power to compressor. Of all things I don’t have a spare relay, so I ordered one of those to try to rule that out. I don’t think that is it, but need to be positive.
They way it looks there has to be a pressure switch somewhere to activate the compressor since the dash switch have only vacuum lines on it? Thanks for the replies!
Click to expand...
There is also a high pressure switch on the line from the comp to the condenser.
Look again on the HVAC controller, there are wires there too.
 
There are wires for the fan speed switch and wires on the hot/cold blend switch but none on the ac switch


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The vacuum lines are for HVAC control for the mode, recirculation doors, etc. The PCM sees the request when AC or defrost is selected. There are electrical connections inside the control you can't see
Here is a wiring diagram I found online that should be for a 99 XJ.
I've seen the high pressure switch fail a time.or two. Many times it is a poor connection at the HVAC to body harness connector.
 

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Back to top. Still no AC. I even replaced the control switch panel out with a working one. I am beginning to think it cold be the pcm ??

Since it has cooled off, AC not as big as a priority. BUT now the damn turn lights don't work :kaioken: where working fine, shut off vehicle for an few hours, go to leave and no turn lights. This Jeep may be working its way on down the road.... I have replaced the flasher relay with a new one thinking that was the issue. Of course not. same thing, flashers work, but not the turn signals. Next replaced the whole switch, must be it if not the relay. Hell no, what was I thinking, same thing. Oh and bulbs are good, did manage to check those as well.
Any ideas on this one?
 
Check the wiring loom at the firewall. I've had it lay against the head and cause odd shit to happen.
 
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