I'm not sure how many of you watch this guy, but I know a few do. His shop isn't too far from me. Anyway, this is a great video on how to properly diagnose a fault and just so happens to be on a 2004 Blazer:

This is a perfect example of why you shouldn't just 'unleash the parts cannon' (to coin a phrase used by Eric O.) on your truck and why so many of us ask a lot of questions when we try to help!

 

Great vid, always a learning process even for us old guys. Thanks for posting

 

Parts cannon. That's funny.

George

 

Like the approach. Get information first, then start fumbling.
No way on modern cars without the complete wiring diagram or even better the electric and diagnostic manual.

LOL like the "getting that jumbo thing up there" - I love my DMM with lab cables and fine points and clips.

 

This is exactly why I like to push people getting a hold of a FSM set or even just a 1 year subscription to something like Mitchells1 or AllDataDIY. For what they provide in terms of information, they are worth the cost for someone that really wants to fix their vehicle. I just work on vehicles for family and close friends. I have 19 different vehicles that I have subscribed to over the past 10+ years with 9 of them being current valid subscriptions in AllData. I get nothing to refer to them either... I just know what works and how much use I get out of them.

Eric O. has all kinds of equipment he just chose not to get out the smaller probes. We've all been there!

 

I’m also a firm believer of having FSM’s for every car I’ve owned, but I’ve never subscribed to either of the two you mentioned, although you’re doing a great job of talking me into it. My latest endeavor this coming spring will be completing dozens of scan runs and tuning with HP Tuners. Like I mentioned earlier, it’s a forever learning process for some of us.

Btw, does AllData or Mitchell provide TSB’s with their subscriptions?

 

I have 5 vehicles on Mitchel1 but I also have shop manuals on a few.

George

 

It has been years since I have used Mitchell's so I'll let those that have used it more recently comment, but AllDataDIY definitely includes TSB information. They aren't as recent as having direct access to GMSi, but GMSi cost $20 for a 3-day access pass so I've never considered using it. For $30, you can get a year of access to AllDataDIY if it is your first vehicle. After that, it's $20/year for each additional vehicle. I tend to go for the 5yr subs though since I know I'm going to be wrenching on things for that long (or longer). Heck, I still maintain a sub for my old 2000 Bravada to answer questions here and I sold that truck over 10 years ago...

 

Mitchel1 has TSB's.

George

 

Always a trade-off on what is quicker. Go fetch the proper cables or go with what you have in your hands. I've relatively lightweight transport boxes that stack on each other with my stuff inside. All handy in reach.

I like his attitude and how to go about analyzing. Also not to throw parts at a problem but to also consider wiring. IMHO one of the major things with our trucks. They are mainly old and even abused. No wonder you have burnt wires, scuff damage, pinched things from offroad or such.
Another thing I have learnt in the forum is to ask for previous repairs. I've gone from chuckles to laughs to "ouch" by seeing how stuff is repaired.

No wonder some things don't work for very long. And it seems to be a sport to do quick fixes and sell the car/truck in a hurry.