First of not sure where this post should be, so sorry if its in the wrong spot. I own a '00 blazer, and it has done nothing but nickel and dime me for the 2.5 years I owned it. Runs great, but had every problem written in the book with it. HEre are my new issues that I need help to figure out.
1- the heat is sorta working. It gets hot, then I can here the vent switch over and it goes cold, then switches over and gets hot, and so on. It has never done this until a couple weeks ago after intake gasket replacement. Not sure if that has anything to do with it. It does this cycle at idle and at speed. Any suggestions?
2- the 4x4 service light is on, and when read shows a no read. None of the fuses are out, and the tccm clicks when the key is turned on, the buttons also quickly flash. But don't stay on. All wires and contacts have been checked and cleaned, and I'm getting proper voltages everywhere. What's the deal? Winter is fast approaching and both these problems need to be fixed, but I'm stumped.
3-windshield wires just keep going. If I spray they go off in about 150 swipes, and if I turn them on then off they will just keep going. The switch was just replaced so its not that. Is there a relay for them?
Thanks in advance

 

the heat, is it full of juice? hear water sloshing in the dash? if not sounds like blend door actuator behind glove box, little black box with a electric servo in it, potentionometer fails and cant''find itself''. think you can get them after market now. just slowly cycles hot to cold.

4x4-need to know if 3 or 4 button. sounds like a 4 button and if a capalable scan tool cant communicate with the tccm its prob toast. the 4 button ones have the tccm behind the passanger side kick panel, water gets in them and buh bye, take apart and look for rusty case and bad pins you wont miss em. i think i saw a flyer that dorman is making these aftermarket for like 125???

wipers are easy, pulse board on wiper motor bad, soooooo common. go to autozone, new life time 22 bucks lol they used to be over a 100 at dealer. just unplug and unscrew cover on wiper motor and replace, leave unit right in truck and follow directions in new part, they are redesigned and seal it up good on reinstall wont take 10 minutes. good luck

 

Yes, coolant is full, and has been burped. That's probably what it is, I can hear the door open and close, and it gives a little whistle when doing it. Yes it is cycling hot cold, hot cold. Is that the technical name for it?
The 4x4 is a 4 button. I checked the tccm for corrosion inside and out. Checked all pins on the box, and in wire harness for corrosion, and looseness, no sign of either. When I turn on the key, it is still running through its diagnostics cycle. And buttons give a quick flash and don't ever come on again.

 

If the TCCM is good I would check the encoder motor on the transfer case next. Depending on what transfer case you have it could be different to remove it. I know there have been other threads on here describing how to do this (I had to do it myself).

http://www.drivetrain.com/images/sto...tration_lg.jpg
This is an exploded view of the transfer case and number 10 is the encoder motor. Its for an NP233 transfer case but I'm sure you could find a similar exploded view for your transfer case.