LawDog88

Welcome Juno115. I agree with what you have to say.. I had a bad thermostat at one point, had it replaced under warranty, and have had 0 problems since.. My suggestion, replace thermostat, and have the dealership do it if possible.. Save you a lot of hassle, but not a couple bucks.. Trust me when I say, it would be worth it to pay to have it done, if you have to.

whopper

x2

If/When the CEL comes on, check for a P0128 code which will be generated infrequently when the stuck-open thermostat causes the engine to be slow to reach operating temperature.

FYI - when the analogue gauge drops to 0, and the digital display shows "----" your A/C will likely also be disabled -all due to the thermostat being stuck in the open position.

https://www.chevyhhr.net/forums/problems-service-repairs-42/temp-gauge-c-stoped-working-37675/
https://www.chevyhhr.net/forums/how-tutorial-library-21/how-save-%24350-00-thermostat-replacement-2-4l-p0128-24493/

If you change out the thermostat yourself you can save some serious $'s - my dealer wanted $300 to replace it - and others reported major $'s as well.

Juno115

I actually read the informative How To FAQ here on how to replace the thermostat and did it myself. It took me about 1 hour not rushing including clean up of garage and putting tools away. Hardest part was clearing a path near the driver firewall to get at the hoses and using a long extension to remove the 2 bolts holding down the thermostat housing. It is worth saving several hundred dollars for an hour of your time if you are slightly mechanically inclined. Just remember be very cautious tightening thermostat housing bolts as aluminium strips and breaks easier than you night think.

ImNewHere

I'm replacing the thermostat tomorrow.

I had the things with the traction control light, POWER STEERING in the DIC, and the jerky shifting thing happen again, and while it was going on I lost the speedometer, outside temp, trip odometer, average speed, and fuel economy. I would get a loud clicking, like a relay coming in and out when I got a response from the speedometer and the rest of the stuff started working, then another click when it went back out again. This time I got no codes other than the P0128.

I want to have my computer hooked up to it while it is going on so I can see if I can pinpoint what the issue is. I have an ElmScan 5 and OBDwiz software running on an Acer Aspire netbook with a dual core processor, 2gb ddr3 ram, and Windows 7 home premium. When I had it out this afternoon and had it monitoring and recording the data from a 20 mile trip nothing happened at all. The car ran perfectly. I really want to know what is causing my woes.

Juno115

I guess you'll have to wait and see how things go after the thermostat is replaced. At least you do have some tools to monitor the engine control module ECM if a problem does crop up.

oneton

What about the under hood fuse box, It seems that was a place alot of strange things would come from until repaired/replaced. Also wire harness rub on eng. block somewhere. Think there are TSB on both .

oneton

found this Engine harness chafing at TPS signal J7720 Bulletin 08-06-04-022B 9527 WC 2.20

ImNewHere

Thanks. Those are places for me to check now.

ImNewHere

Well, got the new BCM in, replaced it, and now everything works fine.... except the radio. All the weird twitchiness the car did is gone, CEL is gone, all gauges work, power steering light is off, etc. In other words, all my original issues are gone. Of course the new one did not have a powdery white residue in some of the fuses. Now my problem is that the radio says "locked" on it. Is there any way for me to reprogram it or will it take a trip to the dealer? If so, any idea how much this will cost me?

843de

It'll take a trip to the dealer to unlock the radio, some dealers charge between $30-60 to do it, yours might do it for free if you ask.