BruceB

I replaced the fan speed selector switch about 7 years ago when the connector started to melt and fill the interior with smoke. I cut off the connector and put thermal connectors on each wire and did away with the connector. I also replaced the Blower about two years later as it start to make a ticking sound that got progressively louder over a 3 week period. Have had no issues and living in Central Florida the a/c is constantly on.

About 3 weeks ago the blower would only work on high. Most common cause I read was the Blower Motor Resistor. I ordered on from Amazon, which was an Omix brand. After install, every fan speed worked, but the three fan speed selections that go through the resistor would vary in speed, and on the slowest speed setting the fan would sometimes shut off. I assumed like most other things with the Jeep, it wanted a Mopar resistor. I ordered one, installed it, and an hour of driving, none of the slow speeds would function, and it would only function on high. I went to a parts store and purchased a BWD resistor which has two similarities to the Omix resistor, they have the identical markings and part numbers and both have varying speed when on any of the lower three settings.

By varying speed I mean the rpms of the blower go up and down enough to be very noticeable when on any of the lower 3 settings, but not on the highest speed.

Question, will this cause any type of problem, i.e: fire, electrical problem, overheat the speed selector ect..
Second question, is there another issue that is causing this that I can check?

Thanks...

jordan96xj

Probably low voltage caused by resistance at the ignition switch connector. Open the shroud around the steering wheel and inspect those wires. If you use the blower on high frequently, and for long periods of time. That connector is probably cooked and experience high resistance. You can usually feel the heat is producing by placing your hand under the shroud. If you were actually touching the wires it would be hot enough to burn you. Eventually, it will melt down, catch on fire, etc, and probably lead to a no-start no-run type of condition.

If that connector seems fine, then a similar thing can happen at the HVAC mode selector.

The reason being is that in 96 and older, the full amperage for the blower fan runs through these circuits. Which they are not really robust enough to handle for long periods. At least the resistor is designed to be in the fan's airflow, but the ignition switch and mode selector have no airflow at all. Later models redesigned the arrangement so that the high current/amperage is not flowing through those components.

awg

I am still awaiting to fix 4 relays inside, adjacent to the resistor pack, and powered from the battery.

There is no other way to fully overcome the design flaw

otherwise full current runs thru metres of wiring, ignition switch, fan switch etc etc

Unfortunately, ill health has prevented me working on any of my vehicles for 2 months

BruceB

Sorry about the size of the picture...
Seems like the blower speed switch is the culprit. I am waiting for some epoxy to cure as the ears on the HVAC control have cracked or broken off. Will put everything back together tomorrow with a new resistor and see how we do.

BruceB

also to add, all the ignition wires looked good, no discoloration or dried insulation....they actually looked brand new,,,lol

BruceB

okie dokie Jeep wizards...replaced the switch, put everything back together, started the Jeep and turned on the fan on the "vent" setting and immediately fried another resistor and this time the fan would not go on high..... only had it on for lest than 5 seconds and shut everything down. Including a pic of the ignition wires and you can see they are good, clean, no discoloration of brittle insulation. My question is could a blower going bad cause this, or is there another electrical gremlin somewhere that I have to hunt down

awg

I believe the biggest risk is that the fan can become faulty, and pull a transient start up current of over 20amps, frying things in the electrical chain, (but not blowing the fuse)

I have a spare fan for my '96, and afaic I took it out via the engine bay (the cylinder head was off), but I dont know of any way to test for that situation

BruceB

So I hope this to be the final update/

I removed the blower and found that the fan wheel was very hard to turn. I order a new blower motor and fan assembly. What a nightmare with FedEx, but that is another story. I went to install the new blower motor and realized that the air vent hoile is at the 90° position and not at the 195° position as the old blower motor. Made a work around out of some 1/2" tubing and plastic connectors and it worked fine. Apparently as the old blower motor was seizing up, it would cause the thermal fuse on the resistor to blow.