Another odd heater issue...

Ok...So I have a 91 Laredo 4.0 liter with a strange heating issue. I've found a lot on heater issues on the forum already, but nothing that exactly matches my issue (YES, I did the research first). The issue I am having is withe blower motor. I think it is the switch. The blower turns off properly, but on setting one there is nothing, setting two nothing, setting three works properly, and nothing on setting four (leading me to believe it is not related to the resistor pack). Tonight we were driving and the whole thing started working. I turned it down to low and left it for a while and then after I turned the heat off, the problem was back. Personally I think that despite it being a rare problem, it is probably the switch.

Is there a way to clean the switch or is it sealed?

Am I correct in my thinking that it is probably not the resistor pack?

Could it be the blower motor (since we all know these never fail ;-Þ )

Is there any other ideas?

Thanks for hte help.

Matt

daredevil said:

I think it is the switch

Click to expand...

Matt, so do I. I believe you would want to "replace" the switch; they are generally sealed.

anything will help at this point, how many miles on the clock??

Sounds like a switch and/or switch plug. I've seen the plug get hot and melt causing a loose connection..

Good Luck

Nick

When I was doing warranty work for OEM with these resistors, I saw some wierd things. Somtimes (rarely), the little toaster coils in them could touch each other. Maybe, when the resistor gets hot, the coil moves around and touches different stuff. There is also a little wax filled thermal fuse in them that causes the usual highspeed only syndrome, but these don't always blow like they should. If it all gets too hot, it can fry the wiring harness or start a "thermal event".

I guess my whole point is that the resistor is the easiest thing to pull and check out closely.

X2 on the resistor. I had 1,2, and 4 on my 94. Checked the resistor and swapped it with a JY one. Could be the switch but rarely on the pre-96.

205k miles...I still don't think it's the resistor pack...if it were then it would work on level 4 as there is no resistor on that setting. Mine does NOT work on 4, only on 3. I have the day off on Tuesday and I am going to tear apart the dash to see what it looks like in there. I'm putting other stuff in at the same time so I may as well check it out while I am in there. I will let you all know how it goes and what I find.

Thanks for the help.

Matt

Sorry missed the part where you said it does not work on 4.

FOUND THE FIX! It was the switch. Apparently the guy that used to own my rig did some work under the dash. There was a cut wire in the heater switch and one of the five spade connectors on the back were bent over to one side. We took the connector off bent the connector back into position and viola...it works great now.

Thanks again for all the help guys.

Matt