Every since I bought my 1986 Bronco, the heater runs on high. When you try to adjust the temperature it has no affect on the temp it always runs hot unless it is turned off. I almost think the switch is broken on the inside. It's really nice during the winter, but on a spring day when I'm looking for a little cool air flow....forget it...sauna time! Any other ideas?

 

I've got an '84, so I'm not sure if it is the same design. But, when I've dug around in the dash working on my radio, I've noticed what appears to be some vacuum lines connected to the temp control, which then goes over to where the heater core is located. You might want to make sure everything is connected on those linkages.

Just a thought. Hope it helps. I always like to dig around in things and find stuff.

 

The previous post mentioned vacuum lines possibly being the problem. Those vacuum hoses only open and close the doors to your system. What you will be looking for is a cable that goes from your HOT-COLD switch to your heater box blend door. Perhaps your door is just plain ole stuck and could use a little mother-in-law grease to free her up.

 

I'm in the process of putting a new long-block in so I'll check it out. That's what another fiend of mine suggested! Thanks ps can you buy the mother-in-law grease by the 5lb jar?

 

Hey fellas,

Speaking of heaters, my 94 bronco doesn't even have heat, so you guys are lucky. I've got to go to work freezing cold every morning. The funny thing is that my temp gauge says the engine in warm(normal) but when I turn on the heat it just blows cold air. That same gauge however, is swaying back and forth in the normal range like a boat in water. Whats up with that? My fuses are fine, could it be my thermostat?

please help... THE*bronco*KID

Chapel Hill, North Carolina

 

Try replacing the heater core. Its right behind the glove box. Simply remove the glove box door and remove 5 or 6 screws and the heater core is right there. Its only a 20min job. Also inspect the heat adjuster door too. If you replace the heater core you probably need to change the heater core hoses too. They normally need to be cut off.

 

I don't know if it's the same with air conditioning or not (if you have air), but I've gone through about four of the temperature control cables on my non-air '86 truck. The hook on the end of the cable that hooks to the lever seems to be the weak spot where it always breaks. You can see if the cable's broken by turning the temperature door manually under the hood at the heater core and see if the heater temperature changes.

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[font color="green"]1995 F-150 Supercab XLT 4x4 LWB 302 M5OD
1986 F-150 4x4 300 I6 NP435 [/font]Warn hubs, DeeZee bed caps, '96 XLT bench seat, new paint job