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TripleNickle 12-22-2012 12:49 AM

Heater Help ASAP
The heater in my 98 tj works intermittently. I have checked all connections, they seem to all be fine, I can hear the relay click when I turn the fan between high and the next speed down. Any ideas would be greatly appreciated, going out tomorrow morning and want to get this worked out so I dont freeze to death.

RUBI 4 MY MRS 12-22-2012 02:38 AM

Hearing the relay click between high & the other speeds is normal for the '98s. On high the relay closes to bypass the resistor. For the other speeds the relay opens to route the circuit through the resistor to lower the speed. Each of the lower speed settings directs the power through different resistances to get the lower speeds. The question is does it click when switching speeds but the fan not run on either high speed or any of the others? If it is still intermittent when it clicks for high Then it is likely the fan motor itself. If it is only intermittent on the lower speeds then it is likely the resistor but could also be the speed switch. When checking look at all the wires & connectors for signs of excessive heat or melting. As the motors age they can start to drag causing added amperage draw & overheat the wiring &/or resistor.

Note that this all changes in '99 when they changed from the slider controls to the 3 dials on the panel.

TripleNickle 12-22-2012 09:18 AM

It does NOT click on lower speeds just going from high to the next speed down. I did get the motor to work for a while when I slapped the bottom of it. After reading Im thinking a motor or a loose connection. Another Forum member in alaska had the same issue and it was the motor. I will check all the wiring. Any other thoughts would be appreciated.

TripleNickle 12-22-2012 09:25 AM

When I went to bed last night it was not working at all, I just went into the garage and what do ya know it was working! I forgot to mention in the past it would work until I shut my jeep off, then when I turned it back on nothing. Drive around or wait, turn the jeep back on and BAM its working again.

RUBI 4 MY MRS 12-22-2012 11:53 AM

First understand the Alaska TJ was a later model & the whole circuit changed in ’99 when they went to the 3 dial control panel. The diagnostics are completely different.

Yes the relay only clicks going to & from high speed. That is how it supposed to work. The question is after clicking over to one speed & not changing the speed setting will it cut out &/or simply quit while driving around. If yes then it is either a bad (lose or melted) connection or the motor is going bad. If it cuts out when switching from one speed to another then it is also possible that the speed switch or resistor is bad.

The easiest way to test it is on high speed because once the fan is on, the relay is closed & the resistor is completely bypassed. As long as the speed switch is not moved & the mode switch (slider) is not turned off, there are few possible causes if the fan quits when hitting bumps or even “slapping” the heater housing.

It definitely sounds like the motor or connection to it that is the problem. Just check for melting of the wires & connectors when checking it.

jp2611 12-22-2012 12:08 PM

had a similar issue a couple years back could kick or hit the motor on the heater it would than work....very easy replacement.

TripleNickle 12-22-2012 07:35 PM


Originally Posted by jp2611 (Post 3132679)
had a similar issue a couple years back could kick or hit the motor on the heater it would than work....very easy replacement.

So yours was the motor it self?

jp2611 12-22-2012 07:58 PM

yep....replaced everything okay for a day or 2....than nothing...if I left switch "on" sometimes when I hit a bump it would start working...that is how I figured out the hitting kicking it ti start motor was about $140 and 15 minute swap time use a mirror and changing motor thread is actually on here very simple once you understand how it goes in.

I switched my blower motor 2 years ago.....still good.


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