I have recently purchased a 1997 Ram Van with A/C that is causing me some issue. The blower Fan works fine through all 3 speeds when the system is set to max A/C. But as soon as you switch to any other setting, such as Heat or Defrost even the lower settings of A/C, the blower Fan stops working. It dosent blow at all.

I have gone to the Junk yard and purchased a climat control switch and the blower motor functions exactly the same, only works when the system is set to max A/C. I have ordered the repair manual on the van but do not have it yet. But I'm hoping someone on here might have some insight on where to start? Also does the Haynes repair manual have a decent wiring schematic section?

 

http://motors.shop.ebay.com/__?_from...manual&_sacat=

The Haynes are hit and miss.

The above manuals will have detailed wiring diagrams

 

Did you check all fuses inside and under the hood? The A/C might have a separate fuse which is why it still works and the heat setting doesn't.

Of course the junkyard switch could've been no good too.

 

Have you looked at the Blower Motor Relay?