Heater Motor Fan Problem

[RNewkirk]

Here is a strange one (to me). At times my heater motor fan will not come

on. I notice that when this happens that when I shut the truck off and take

the key out the steering wheel is not locked.



If I turn the key one and bounce the tilt wheel up and down a few time I can get it to work for awhile.



This is on a 2003.



Any thoughts on what is going one here?



Thanks

 

[rbattelle]

Wow, that's a new one! Sounds like it might be a problem with the ignition cylinder not correctly registering key position.



If it were me, I'd check for voltage at circuits that are supposed to be at 0v when the key is "OFF". If you find any that are getting 12v when the key is off, then the likely culprit is the ignition cylinder.



If the problem is extremely intermittent, diagnosis becomes much more difficult, of course. In that case, I'd make a simple monitoring circuit (or use an old voltmeter) to indicate the voltage in a circuit that is supposed to be at 0v in the "OFF" position, one that's supposed to be at 12v in the "ACC" position, and one that is at 12v only in the "RUN" position. Then, when the heater blower acts up, check each of those lines. If any don't match expectations, replace the ignition cylinder.



Of course, there's always the option to "throw some money at the problem" by simply buying and installing a new ignition cylinder. You gamble that's not the problem.



-Ryan

 

[DPKetchum]

Elect. part of the igntion switch going bad. Seen it on MANY vehicles over MANY years. Try a little wd/40 first. Sometimes a funky or worn key will do this also.

 

[RNewkirk]

Thanks for the fast replys. No heater motor fan makes for a COLD truck when it is 7 degrees out like this morning.



I will give your suggestions a try.