This is my thread:
That video is wrong. Not even close. The relay to replace is in the IPDM. There is a pdf in the link indicating what relay to replace. You have to pull the IPDM and open it up. However in the past I have had odd electrical problems such as the ECU and cruse control failing. I ended up with a $2k+ repair bill. I suggest replacing the IPDM if the 2004 model year replacement part is NOT the original but an upgraded part. This is also in my thread. Basically the new IPDM is black and comes from a different manufacturer than the white one in your truck. The 2006 model year was when they changed suppliers.
Replacement is easy. Disconnect the battery cables. (I can't imagine why they suggest both cables, but this is a good opportunity to clear the terminals,) Wait 5 minutes, presumably to let some capacitor(s) discharge.
You disconnect all the cables to the IPDM, pull old IPDM, drop in the new IPDM, then plug in all the cables you disconnected. Every connector is unique so you can't make a mistake.
You have the usual issue to figure out what trick the connector manufacturer uses to release the cable. Push this or squeeze that. My dominant hand has nerve damage, so this is really annoying, but still it was a 15 minute job for me. The cover has to be replace because fuse locations have changed. For the 2006 model year, I listed the part numbers.
That said, it turned out I needed a new starter, and on the 2006 model year, that is three hours work due to crap in the way. I would buy the starter online and take it to a garage you trust.
Check out this page for the insanity involved to replace the starter:
For a 2004 model year, figure that IPDM served you well (or maybe not), but you got your mony's worth, so put in the upgrade. Note that the parts department will know about the new replacement part, but of course the part is at least $100 cheaper on line.
I got all my parts (IPDM and starter) from
The advantage to Coulter is they didn't require shipping back the old starter. The thing is heavy! Who knows, I might have to replace the starter again since the last one barely made 130k miles. It was flaky for at least a year. The problem is there are so many things in the truck that can cause odd starting problems AND the problem was intermittent, making it hard to diagnose.