Heater control not working (just hot)

chopper007

chopper007

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Joined
Jun 20, 2024
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Huddersfield, uk
Hi All, so day 2 of owning the Jeep, things at the moment sitting pretty well tbh.
BUT, ( and I have read through a few of the threads ), the heater control ( which on this 2006 is a rotary ) isn't selecting AC. it just blows hot all the time.
I was just with my mate, and the AC is most def working, the send pipe work under the hood is ICE cold, and the return is hot. so it's the selector switch or something between that.

I have read this can be vacuum controlled, but my mate also said it could be an electrical switch, the fan control etc is all working fine, so there is power to that panel.
thoughts, help, images ( always good ) and if you think I need parts resources in the UK if possible.
before I start taking things apart.

thanks all.
 
Pull the knob off first and check it for cracks. I've had three Jeeps do that.
AC Heat knob.jpg
 
chopper007 said:
Ahh thanks, just had the dash apart and that module out, the switch turns ok, and can feel the graduated position, the electrical connection on the back is somid too
Click to expand...

HI All, so thinking this might be the actuator's / doors etc. this is a RHD jeep, found the motor and it's not moving, anyone know if / where the fuse for these is I can check, next is to order a new one, I can see some on Amazon and ebay( if I found the correct ones), but a couple weeks to ship to the uk
 
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Looks like the amazon one should fit. Might be worth opening your old one up and giving it a clean first. It may be that it's gears are just gummed up with old dried up grease.

The wiring to it isn't shown in the 06 FSM, but based on the 05 the power comes from fuse 8 behind the glove box.
Since that also supplies the blower motor relay, if the fan works the fuse is good.
 
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jonny jeep said:
Looks like the amazon one should fit. Might be worth opening your old one up and giving it a clean first. It may be that it's gears are just gummed up with old dried up grease.

The wiring to it isn't shown in the 06 FSM, but based on the 05 the power comes from fuse 8 behind the glove box.
Since that also supplies the blower motor relay, if the fan works the fuse is good.
Click to expand...

Yeah, ive had the old one open, put 12v straight to the motor and didn’t even try to move, so figured it’s burnt out, will order a new one and see, problem is I don’t know where the dial was when it failed
 
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It may be a stepper motor, and need multiple pulses to move it a fraction at a time, based on the input to the motor from the variable resistance at the temp switch.

I'd try cleaning it and plugging it in to the connector to see if it moves with ignition on and changing temp knob.
 
jonny jeep said:
Looks like the amazon one should fit. Might be worth opening your old one up and giving it a clean first. It may be that it's gears are just gummed up with old dried up grease.

The wiring to it isn't shown in the 06 FSM, but based on the 05 the power comes from fuse 8 behind the glove box.
Since that also supplies the blower motor relay, if the fan works the fuse is good.
Click to expand...

No joy with the motor, tried it this morning after a strip and re-lube etc no movement at all, the switch feels good, but I guess it’s possible the electrical side of it isn’t..
 
Cleaning the motor may have worked so it was worth a try.

If you have a multi-meter to check the connector. The dark blue/white wire is ground, orange is ignition switched 12V. The third yellow wire should vary in voltage as the temp knob is adjusted.
 
great advice, very helpful thanks, I have metered, and can report everything wore wise works, 12v on the blue&red and when I turn the dial the voltage changes, I can also manually move the flap, so that's not stuck, I have ordered the Amazon part, will see if it works when it gets here in a couple weeks, in the mean time I'm now manually set to Ac :cool:.
I have a feeling my Heater/core/matrix may have a small leak somewhere, when I'm running I have a faint Wiff of hot coolant, I believe that's pretty much a whole dash out job ?

thanks again Charlie
 
Yes, heater core is a dash out job. The RHD heater core is a mirror image of the early LHD heater core.

I don't know if there are any RHD aftermarket heater cores available. I paid £280 for a genuine one several years ago from a Jeep Dealership. That was with a discount too, as a friend's son in law worked there at the time.

Edit: looks like there are a couple of aftermarket cores on eBay for £135-140 posted. Use heater matrix to search through as that's what they are generally called in the UK.
 
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jonny jeep said:
Yes, heater core is a dash out job. The RHD heater core is a mirror image of the early LHD heater core.

I don't know if there are any RHD aftermarket heater cores available. I paid £280 for a genuine one several years ago from a Jeep Dealership. That was with a discount too, as a friend's son in law worked there at the time.
Click to expand...

Dam, anything else I can check before I open up the dash to look , and the IF I need one find a replacement , tbh I had thought it would just be the same part, I hadn't considered there would be a LHD 7 RHD version.
 
There's a drain tube that exits the firewall on the passenger side. If the heater core is leaking it should drain out of there if the leak is big enough. You should also see the coolant level dropping in the overflow tank if you have a leak anywhere.
 
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