Hello folks this is my first post So my jimmy " 4x4 4 door auto" has a few problems that are kinda strange, any help would be great. Just bought it

1) temp guage will only move to the first line ( changed sensor ) no help

2) very little heat ( I would assume heater core ) Engine does not seem to get warm though.

3) Ses light will not come on all the time with key on, maby 50% of the time. My understanding it should come on with the key then go off after a few seconds every time. I also noted it would not trip the light if I unplug the maf sensor, scan tool picked up the dtc however. Plugged it back in of course.

All that being said the the truck drives fine.

 

Sounds like you need to replace your thermostat, not sure about the light probelm though.

 

The instrument cluster is controlled by the BCM, (Body Control Module). The various onboard computers communicate using class II serial data. Without using a scan tool capable of accessing the network, troubleshooting is next to impossible. Something you can try, is remove the cluster and make sure the pins are secure in the electrical connector, the connector is tight, and the pins are mated to their respective sockets.

 

Thank you guys, I'm going to test some more stuff in the next few days. The IPC and heater core is suspect atm. Will keep you posted

 

I think 50lb_cat is spot on with a bad thermostat, and possibly low coolant level.

 

yea gonna change the thermostat tomorrow, coolant is good.

 

Bad thermostat was the problem for 1 and 2

 

i also have a 2000 gmc jimmy with automatic climate control and its been pissing me off. the heat dont seem to be as hot and it fluxuates with cold and warm when its on max setting for hot. it also dosent fluxuate through all the climate modes it usually blows at my face all the time. ive changed the climate control panel 2 times and checked for vacum leaks. ive also replaced the vacum sylanoid panel behind the dash and i still have the same problem. i have green coolant and new thermostat and my heat always sits at 1/4