GMC Repair: 1998 Jimmy - Heater and ABS ?s, obdii scanner, fan controls

Question
1- Just picked up a 1998 Jimmy that needs a little love.  First issue is that the heat seems to be maxed at all times.  It has the auto climate control set-up.  Fan controls work ok, recirc works fine, but it blows hot regardless of the temp setting.  Also, if you press the AC button the indicator light flashes a couple times and then turns off.  The compressor clutch never engages, on AC or def settings.  Second question- ABS light comes on and stays when the vehicle is started... front speed sensor resistances look ok, and I also checked the ground behind the LH headlight (heard that was an issue).  Have not had a chance to get it scanned yet?  Any ideas?  Can you recommend an OBDII scanner that will do engine and ABS?  Thanks

Answer
Hi
As far as scanner, alot now do ABS and PCM. Check autozone, NAPA, etc... it will probabally depend on
1) how much your gonna use it
2) how technical you want to get.
The less expensive ones will ONLY give the code. Thats it. Justa  code number.
The more features you add, the more they aid in diagnosis and repairs.
The ABS you should get it scanned. I have repalced ALOT of front sensors, even when they ohm out good. the resistance can check good, but when voltage is applied, it may drop too much voltage and the pcm sees this. Anyway, get it scanned...it may be something different.
Try on the HVAC controller, try to unhook BOTH cables from the battery. Then touch them together for about 1 min. Then reattach the POSITIVE first, then negative.
See if that clears up Logic Lock.
If it still acts the same, you can also then see if it is storing any codes by having it scanned also.
I hope this helps in some way.
Good luck and follow post back, if needed.
Pawl