Hello. I have a weird problem with my truck. When you try to turn the heater fan on, the ABS light comes on, and the heater fan does not turn on. This problem sometimes goes away for a few miles. I checked all grounds, in the engine compartment, and in the dash, all OK, and cleaned. Removed the heater fan, looks and runs like new when tested with external 12v source. Removed heater switch, and resistor, all look good. Any adwice what to check next? Thanks

Check the fuses and fuse holders for corrosion. The schematic I'm looking at shows the fuses for both systems are under the hood.
If they look fine, you may have a problem with connections in the fuse box itself.

I've got the exact same problem! :mad:

It was the ignition switch. the contacts were burnt.

That is one thing I like about this site. You are working on your truck and stumble on a problem. You log in and make a post about the stumbling problem. Then before anybody has a chance to help you out you figure it out on your own. Maybe by mistake!

To me this site is a great place to vent your problems when you are working on your truck. I know I do this but, I have not done it here yet. I usually do it at the truck with lots of curse words I can not post here.

This site is great!

Glad you got your truck back up and running! Thanks for posting the finishing results. It will help somebody else in the near future.

I'm having the same type of problem. Were you having problems with 4WD as well? Mine won't engage. Mechanic told me actuator, so replaced it. No go. Also cruise control flakey. I multimetered the heater and 4WD, and it seems I'm only getting 9 or so volts there. I got a wiring diagram from somewhere on this site I think. Seems the orange wire (E) circuit from the ignition switch feeds all that stuff, so I'm fairly convinced that I need to replace the ignition switch.