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Help needed with heater controlls cutting out


Guest the--daddy

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Guest the--daddy

hey guys, first post on here could do with some help.

i've searched similar posts with not much luck.

 

My heater controlls work fine as long as temp dial is not turned just below half way down. as i turn temp dial to cold all power cuts out to everything to do with heaters. I have fiddled with one of the motors under top glove box on dash and it seems to restore power, well untill i turn temp down again and everything just dies.

 

So basically its a sweat box as always bit of hot air blowing out.

anyone had same prob.

any help would be great. Cheers

 

j-spec aerotop 93

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Guest the--daddy

still original led's mate, been doing it a while but didnt bother me too much in winter. as i say everything is fine till i turn temp down, oh one thing i forgot was ac doesnt work either if thats anything to do with it

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Guest the--daddy
Might be worth just getting a new heater control unti from a breaker on here. I know it's a bit of a cop out, but it'll almost guarantee a fix and shouldn't cost too much.

 

you think thats the best thing to try any idea on price i should pay for one? cheers

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  • 2 weeks later...
Guest the--daddy

UPDATE!

Changed heater control unit, still the same problem.. when the motor arm under top glove box tries to move over to cold, it just sticks and all power to heater dies. to get it working again i have to push lever back to hot position with a screwdriver....

any more ideas on this one guys??? cheers

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Is the arm fouling on something?

 

Your AC might not be working as it's always on hot. When you press the Ac button, do the engine revs rise and fall with the AC cutting in?

 

Find the motor that moves the arm to control the heater valve and see if it is fouling on something. When you push it back with a screw driver, does it move smoothly, or does it feel like its grinding on something?

 

Clean and re grease the joints in the arm, it may be that it's getting stiff with age, and the resistance is causing it to cut off.

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Guest the--daddy
Is the arm fouling on something?

 

Your AC might not be working as it's always on hot. When you press the Ac button, do the engine revs rise and fall with the AC cutting in?

 

Find the motor that moves the arm to control the heater valve and see if it is fouling on something. When you push it back with a screw driver, does it move smoothly, or does it feel like its grinding on something?

 

Clean and re grease the joints in the arm, it may be that it's getting stiff with age, and the resistance is causing it to cut off.

 

got dash of at moment should be back on tonight so i'll check the revs when i press the ac button.

 

when i push it back it is stiff to get going but as soon as it moves a little it glides straight back over to the high temp position, could it poss be the motor do you think, cant qhuite get to it properly without the whole top dash off might take it off tonight before i put dash panels back together, i'll let you know.

Jon

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When you tried the AC, did you have the heater dial on cold setting?

 

if you did. you're AC is not cutting in, which could unfortunately, mean a number of things. When the system runs out of gas, it simply stops the pump running. So it may mean that it's simply out of gas.

 

With regard to your problem with the cutting out, I'm afraid I'd need to see the car in person to say any more. My dash is out at the moment so I'll have a quick butchers at the mechanism to see if I can make out what the problem could be.

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Guest the--daddy

Your a good man, its driving me nutty!!!

when put a/c on can't put temp down to cold as it loses all power to heater, can turn it just over 3/4 of the way then it dies.

think i will have to remove full dash to see it properly, as you remove top glove box it is the motor/ arm to the very right as you look at it, when it tries to move right it moves prob 3mm then it dies.

cheers again.

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As you say there is an actuator arm and motor on the top of the heater matrix which moves the flap to shut off the hot air supply. If that's sticking it might well be causing it to trip out the curcuit.

 

Unfortunately to get to the matrix proper is possibly the most difficult job to do on a supra, then entire dash has to come out: http://www.mkivsupra.net/vbb/showthread.php?t=127044

 

The thread above might also give an idea of the actuator involved.

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Guest the--daddy
As you say there is an actuator arm and motor on the top of the heater matrix which moves the flap to shut off the hot air supply. If that's sticking it might well be causing it to trip out the curcuit.

 

Unfortunately to get to the matrix proper is possibly the most difficult job to do on a supra, then entire dash has to come out: http://www.mkivsupra.net/vbb/showthread.php?t=127044

 

The thread above might also give an idea of the actuator involved.

 

oh be jesus! lol, your a legend and a heartbreaker in one sentence dude, that is the one i'm talking about in the dash off pic. looks like i'll be busy this weekend, is it likely to be sticking or do you think i could need a new one, it just sticks then like you say shorts it out. thanks mate

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oh be jesus! lol, your a legend and a heartbreaker in one sentence dude, that is the one i'm talking about in the dash off pic. looks like i'll be busy this weekend, is it likely to be sticking or do you think i could need a new one, it just sticks then like you say shorts it out. thanks mate

 

Sorry to pass on the news mate, it's never easy to say what's involved with the dreaded heater matrix change!

I've never done this myself so can only pass on some ideas of what might be the cause, it might be that actuator, but could easily be something else (Though I don't know what to suggest).

 

If you do end up pulling the lot it'd be a good idea to change the matrix at the same time just as a precaution.

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