99 TJ heater will not turn off Help!!!!!!!!!!!!

can someone please help me with my heater fan on with out the heater being on and it can get hot at times i jeep and would like to able to use the fan but cannot because if I do I would be turning the heater on also I do not know if this may have anything to do with the heater problem but a few months ago when I was at school I had a dash board fire and melted the heater control to where I could not use it and so I replace it with a new used one I got a wrecking yard but after a month after the fire and replacement heater control was installed I got this problem am not sure what to do I have been checking posts but I have not found anyone with the same problem as I do so I am turning to you guys again. My rig is a 99 wrangler sport 5 speed stick 6 cylinder engine no ac

Thanks ahead of time Jamie

Reply to
Jamie Mello
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can someone please help me with my heater fan on with out the heater being on and it can get hot at times i jeep and would like to able to use the fan but cannot because if I do I would be turning the heater on also I do not know if this may have anything to do with the heater problem but a few months ago when I was at school I had a dash board fire and melted the heater control to where I could not use it and so I replace it with a new used one I got a wrecking yard but after a month after the fire and replacement heater control was installed I got this problem am not sure what to do I have been checking posts but I have not found anyone with the same problem as I do so I am turning to you guys again.

My rig is a 99 wrangler sport 5 speed stick 6 cylinder engine no ac

Thanks ahead of time Jamie

Reply to
Jamie Mello

Reply to
Jamie Mello

OK.....

As far as I know, they started using a flow through system back in the YJ's where there is no 'off' for the fan speed switch so unless you turn the climate selector to 'off' the fan is always on.

This means you simply turn the climate selector to vent and the temperature control to cold and let the fan do it's thing on it's own low or give it more.

Once you have fresh air coming through which will take a little bit of time, it will blow out the residual heat left over from the hot heater core sitting under there and blow fresh air in.

You then can put the selector on defrost or heat and get the same outside air.

If you want to eliminate the heat source of the active core sitting in the heater box, you have to add a valve to the heater line out under the hood and shut off it's coolant.

On the Cherokee, they put a water valve under the hood so the heater core actually shuts off. I don't 'think' the TJ has this, but could easily be mistaken. If it does, then this valve has issues, either vacuum or mechanical. The Cherokee one defaults closed with no vacuum.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail > can someone please help me with my heater fan on with out the heater
Reply to
Mike Romain

OK thank you I think I will try putting a valve on the heater hose sounds like it would be the easy way out I will do that when I change the Radiator out. Thanks Jamie

Reply to
Jamie Mello

I had a similar problem in my 2000 TJ. Actually, the heater control board melted nearly 3 times. Specifically, the speed switch on the left would always melt. Finally, everything melted, including the connector to the speed switch. Everyone online and the parts counter indicate this is a very common problem.

I think there was a TSB to add more grounding points for your year Jeep.

You can purchase a speed switch separate from the assembly. Also, make sure to replace the "resistor block" underneath the blower fan (passanger side foot well). The resistors can go bad or possibly the diode. This could cause a short.

Search this group in Google for my name. I have some posts on how to solve the problem. Also, part numbers to order.

Good luck, Nick

Reply to
Nick Hughes

Ok I will check that out. Thanks

Reply to
Jamie Mello

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