With the cold weather my Hummer has developed some strange problems. I think some of it might be grounding, but don't know where the grounds are or how to check them all. Any suggestions....

1. When the temperature gets to freezing my speedometer advances to about 80 mph and sticks there. I can tell how fast I go until I get to 40 mph (120 mph indicated) then it's just a guess. If I disconnect the battery for about 1/2 hour it will go back to normal, but only for a very short time. When the temperature rises it seems to work OK. I'm guessing this is the old bad instrument cluster, but it only happens in winter (happened last winter, but never over the summer).

2. My windshield Wipers don't operate normally any more, and I've only noticed it since the weather has gotten colder. They either only work on the fastest setting, or they work normally, but won't shut off until I pull the fuse. (I think this might be a ground, but I'm not sure.)

3. My Navigation radio will not go into night mode and dim down normally. Sometimes though when I'm driving it will just change, it might be day or night and it makes the change to either dim, or bright (it's most often on bright).

Dont have a Hummer dealer in town (nearest 100 miles away) but the Chevrolet dealer said to bring it in and they'd put it on the computer. I've hooked it to my OBDII computer and read no codes. Anyone know if they dealer's computer will read more? Can they hook it to the Tech 2 scanner and find more about this stuff, such as if there is a bad ground? Don't know much about these computers but I don't want to pay $100.00 for them to tell me "the computer shows no codes", which I already know.

Thanks, let me know what you think.
2003 H2

 

I dont think your crazy. I thought I was Alone man. My SUT does the same thing the last 3 winters. speedo starts acting up the same way. the voltage needle goes off the chart.My left turn signal has been replaced 3 times by the dealer along with all new wiring and harnesses. it works when it wants too when its below freezing. I have been told to try having a few good grounds installed in the truck to see if that helps. I gave up and I bought a garmin navigation and had it mounted over the speedo and use that as my new speedo. Guage cluster is like 650 from what i heard the navigation was 250.

 

As a followup to my question,

I went to the local Chevrolet dealership (nearest Hummer dealer 100+ miles away) and tried to replace the Wiper pulse board to see if it would solve my wiper problem, they offered to order me the whole wiper system for a little under 400 dollars. I said I'd try something else. I took the pulse board home, cleaned, and dried it thensealed it (at least I thought I'd sealed it) to the wiper motor and re-installed it.

Everything worked fine, and I mean everything, speedometer, Radio, everything. We had snow over the weekend, and it's starting to warm up today and everything is wet once again. I was driving down the road and my wipers jumped a little and I thought, oh no. About five seconds later my Navigation Radio changed brightness, and the windshield wipers started working (they were still turned off). As of now the speedometer is OK, but how long that will last is just a guess.

While I'm not a mechanic, I think the problem is with the water on the wiper pulse board. I found a new one, and ordered it and won't drive my Hummer until I can replace it, and seal it quite well. Hopefully it will come with a cap because I guess my old cap must have a problem and is letting water in.

It seems unusual that a problem with the Wiper pulse board would affect other things, but I did not have the problem after I cleaned and dried the board (even though it was raining that day), and did not have problems again until I had a lot of water on the vehicle again. Could be something else associated with water, but when it was good and dry, all, I mean all the problems disappeared.

I don't mean to suggest that anyone with similar problems might solve them by drying the pulse board on the Wipers, but it worked for me for some reason and I hope next week when I replace the board all my problems will disappear again.

 

HA!! When it's cold my alarm system will not unarm. Imagine that. Happened 5 times last winter.

 

havent had any problems with the wipers. I put my H2 in the garage which i never do and drove my Girls car for the last 2 days. I started the truck up and everything worked!! The speedo voltage and side marker light ... I put about 150 miles no problem then i came out of dinnerearlyer and the speedo, voltage and sidemarker light are not working now!! Im putting it back in the garage to see if it does the same. For the amount of money I spent these little problems shouldnt happen. I was looking at an 08 SUT but i dont want any bull**** if i lay out another sixty plus to GM you know what i Mean.