Hi there, I'm hoping someone here can give me some advice. I have a 2004 2500 Diesel and my heater blower quit working. It went through a short period where it worked, then didn't work, then worked again, but now appears to be dead. I tested the motor with direct 12v and it works fine, so I figured the resistor was the problem so I replaced that but that isn't the issue either. For about a year, I had a problem at times with the blower motor staying on after the ignition was turned off and all I would have to do is wiggle the key and it would stop. In doing some research, I've found a couple of bits of information that leads me to believe this might be the issue. I have 12v at the fuse block and the fuse is good, but I have no power to the resistor block. Does this power from the fuse block run through the ignition switch? Has anyone else had this problem or heard of this happening? I have a hard time believing that the heater control board is bad simply because everything else on the board works fine and when I took it apart, I see no signs of circuit failure on the board itself, no carbon tracing or anything like that. Any help would be appreciated, I don't have a dealer within 100 miles of me and would just as soon fix it myself anyway. Thanks for your time

Benoyracing

 

bump it

 

I am certainly no help to you, but I do know I have had the same issue with my fan... mine works most of the time, but once in a while it will stop working. I have not done any testing "electrical wise" as I have know knowledge of doing so, so I can not give any advice. But, I do know that the last time it quit working on me, when I hit a large bump in the road it began to work again (and has ever since).

Good luck with your fan problem, and post up any findings.

 

If there is anyone that has any information, especially with any schematic knowledge that can tell me if that power runs through the ignition switch, it would be greatly appreciated. Thanks

 

Of course it runs through the ignition switch silly. With the key off (in normal conditions) does anything work? Nope. With the key on (not running) do those same things work? Yes

So of course power runs through the ign switch. And from what you said in your first post, you already know if is the switch as you have verified the fan motor works. You have verified regulated voltage at the resistor block. Then yon found if you wiggle the key it will work (ding ding ding - we have a winner )

So seriously, you already know what your issue is. Now you just need to go down to your local auto parts store or online (www.rockauto.com) and buy one and replace it. It is very easy to do but if you have any Qs on how to then you can click on the links in my signature to get your service manual and use it.

 

Thanks! I thought I had it pretty much tracked down, I am just looking for a little re-assurance from someone who has seen this before! I appreciate the help. I know that the power goes through the ignition switch, just didn't know if it went through the ignition switch before or after the fuse box, but I guess it wouldn't be a smart idea to go to the fuse AFTER the ignition switch and leave it unprotected! Do I have to take the key cylinder out to get to that switch? If so, how big a deal is that? Thanks!

 

No problem with making sure. We all have been there before. Ive never taken my switch out so Im not sure. However there have been a few guys who have had to replace theirs. Download the service manual in the link in my signature and start around page 1664