HVAC switch?

I've done a fair amount of searching and haven't seen this particular problem. My blower motor works well at all speeds until I switch it to defrost and then it stops. It Sometimes stops at vent and heat as well but with a little bit of moving the selector around they will work. Never defrost though. This sin't a vacuum thing is it? I'm thinking bad electrical switch contact. JY wants $30 for one and no guarantee that it works. I'd gamble if I was sure I was chasing the right problem.

year?

The way you describe the symptoms, It comes across like one of two scenarios.

Older XJs that have a known electrical problem at the blower motor speed switch. As they age, the blower motor pulls more amperage due to wear. Meanwhile the electrical connections at the switch loosen their grip on their respective terminals and high resistance ensues. This high resistance and increased draw of the worn motor causes heat. This melts the connector at the switch, burns the cardboardish material the switch is made of, and causes funny things to happen.

So you either have problems in there that need looking into before throwing parts at it,
or,
Someone before you has been in there, and screwed up the wiring trying to fix it.

Either way, Take it apart and put your good eye on the blower switch connections. betcha find somethin' interestin'

Oh ya...it's a '93. I have pulled out the whole assembly and gave all of the connectors a hollywood tune up. Nothing looks burnt, melted or otherwise. There was a bit of crud on the connector pins but not much. The vacuum box looked pretty clean. I was thinking the speed switch for a minute but it works fine on all of the A/C settings and once it is on heat or vent you can adjust the speed up and down just fine.

BTW, I have owned this jalopy for the last 6 or 7 years and drove it daily for about 5 of them. It is the spare rig right now and this has happened since last winter.

yep then it's the mode switch.

no guarantee? most yards will swap another with you if they one they give you is bad in some way.

Ya. I may call around to another junk yard. That's all that I am looking for is trade me fro a different one within a week or so. Thanks for the input. I will post an exciting conclusion to this story later in the week.

... And now for the happy ending. Found a different JY today and got a switch assy for $25 bucks. Don't know that I'll go back to that place again, but that is a different story. Cleaned the new one and greased all of the slides up and installed it. Works perfectly.

:yelclap: