Not enough heat
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Senior User
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From: TENNESSEE, GO VOLS
Not enough heat
My heater is only working on the low selection, asked a local mechanic about it and he said it is probably the heat resistor, does this sound right or is it something else. If it is the heat resistor could someone be kind enough to tell me where it is located, and how hard it is to change out. Thanks again.
Lead Driver
Joined: Nov 2003
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From: Campbell River, B.C.
Are you referring to the fan switch? Usually when those fail they only have power in the high mode. I think the switch itself may be your problem.
The resistor it located at the heater case under the hood. Its near the bottom of the forward face of the box, held in by two screws.
The resistor it located at the heater case under the hood. Its near the bottom of the forward face of the box, held in by two screws.
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Senior User
Joined: Feb 2007
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From: TENNESSEE, GO VOLS
Originally Posted by David85
Are you referring to the fan switch? Usually when those fail they only have power in the high mode. I think the switch itself may be your problem.
The resistor it located at the heater case under the hood. Its near the bottom of the forward face of the box, held in by two screws.
The resistor it located at the heater case under the hood. Its near the bottom of the forward face of the box, held in by two screws.
Lead Driver
Joined: Nov 2003
Posts: 6,900
Likes: 3
From: Campbell River, B.C.
The switch is in the dash, right at the other end of the lever for the fan control.
Don't have a price for a new one, but I would expect they are both fairly cheap, your best bet is probably a wrecker though, I don't think you can get these parts at an autoparts store.
Don't have a price for a new one, but I would expect they are both fairly cheap, your best bet is probably a wrecker though, I don't think you can get these parts at an autoparts store.
Senior User
Joined: Dec 2003
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From: Grosse Ile Mi.
blower motor resitor assy is what controls the power to the blower motor the only time it is not used is on high where it gets full voltage.. the resistors fail a lot pretty common.. the connector to it could be melted as well..
Cargo Master
Joined: Nov 2003
Posts: 2,585
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From: Duluth, Mn.
Try cleaning the contacts on the blower resistor. Is common for them to get corroded and fail to make good contact.
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From: Virginia
The blower motor resistor is available from the parts stores. I agree though, that when it fails, you usually have high speed only on the fan motor.
We just fixed one on a 94 f350. It had high speed only. We took the resistor out, and everything looked ok, except there was this little cylinder type thing mounted on the board, and it did not have continuity. We finally figured out this was a thermal safety device, just like the ones they have in coffee makers. It opens up if things get overheated. We bypassed it will a piece of solder, and it worked. We were thinking if things got hot again, that possibly the solder would melt and shut things down. The only scenario I can think of when this safety thermal device would be needed, is if the bearings in the blower motor would lock up, so there still would be current going through the resistor network, but there would be no cooling air flowing over it. I have had them out while the fan was running, and the speed resistors get red hot.
We just fixed one on a 94 f350. It had high speed only. We took the resistor out, and everything looked ok, except there was this little cylinder type thing mounted on the board, and it did not have continuity. We finally figured out this was a thermal safety device, just like the ones they have in coffee makers. It opens up if things get overheated. We bypassed it will a piece of solder, and it worked. We were thinking if things got hot again, that possibly the solder would melt and shut things down. The only scenario I can think of when this safety thermal device would be needed, is if the bearings in the blower motor would lock up, so there still would be current going through the resistor network, but there would be no cooling air flowing over it. I have had them out while the fan was running, and the speed resistors get red hot.
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