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AC selector Broken

S

Spearfisher XJ

NAXJA Forum User
Location
SoCal/Maritime Academy
1988 XJ 4.0 AX15

The selector switch on my AC doesn't work. So when I try to go from Hot (red) to cold (blue) it will only go about 3/4 of the way into the cold section.

Also, my heater blows warm air, but not hot air. It will warm up the XJ in the snow but it takes a very long time to get it there. Is it the heater core?

Thanks
 
Up under the dash on the passenger side you can see the cable that operates the blend door. That's the cable that goes to your heater control slider. See if something is messed up under the dash.
 
cruiser54 said:
Up under the dash on the passenger side you can see the cable that operates the blend door. That's the cable that goes to your heater control slider. See if something is messed up under the dash.
Click to expand...

Related question. I have noticed that my front vents have no air flow while on the heat setting, regardless of the cold/hot setting. Is that normal?

I either have a damper door issue, or a clogged heater core on my 87 to fix.
 
You probably need to flush the heater core. Try the search function as it has been covered here many times.

Basically, you get 2 pieces of heater hose, 5/8" and 3/4" IIRC, and put a garden hose fitting on one end of each. Connect one to each side of the heater core. Connect one fitting to a garden hose and put the other hose fitting into a bucket, so you can observe the crap coming out. Run the hose for some time until the water appears clear. Then, after assessing the pile of crap in the bucket, dump it and reverse the flow. Keep switching back and forth until the water flows clear both directions. When done, flush the tap water out with distilled water, reconnect the heater hoses and top off the system with 50% AF and 50% distilled water.
 
Last edited:
One needs to very careful doing that with a garden hose, as the line pressure is high enough to bust open a heater core. So either restrict the flow with a valve first, and bring up the flow/pressure very slowly at first or use a small low pressure pump.....!!!!



MoFo said:
You probably need to flush the heater core. Try the search function as it has been covered here many times.

Basically, you get 2 pieces of heater hose, 5/8" and 3/4" IIRC, and put a garden hose fitting on one end of each. Connect one to each side of the heater core. Connect one fitting to a garden hose and put the other hose fitting into a bucket, so you can observe the crap coming out. Run the hose for some time until the water appears clear. Then, after assessing the pile of crap in the bucket, dump it and reverse the flow. Keep switching back and forth until the water flows clear both directions. When done, flush the tap water out with distilled water, reconnect the heater hoses and top off the system with 50% AF and 50% distilled water.
Click to expand...
 
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