'08 Chevy Uplander | Charging System Failure

[JasonMcD]

I bought my Uplander several months ago now. Under normal (dry) conditions, it runs great. However when i try to drive it during the rain, or even if it is a bit humid out, my voltage will suddenly drop from around 14.5v to 11v which causes my power steering to fail. It will eventually snap out of it, but its a big concern seeing as how it leaves me with no power steering.

I took it to my local mechanic shop, who have been pretty reliable at discovering electrical issues in the past..and they told me that it was charging fine, and they could find no issues with it. Albeit, the weather was dry and sunny today. They told me to bring it back in when it is raining and/or having the same issue again.

I have read that it could be anything from faulty battery terminal, to bad alternator, to a bad electronic control module. 

Considering that it only happens in the rain, i feel like it really has to be some kind of short in the wiring system, somewhere from the battery/starter/alternator. I think if the alternator was bad, they would have discovered that in the shop. The cheap fix would be to replace the battery terminals and cables. The ECM is a much more costly job.

Before i start throwing money at it and replacing things, i thought i would ask here to see if anyone has any experience with Uplanders and/or have had experience with a similar issue in their van? Thanks in advance.

 

[bullfrog]

Get a spray bottle with some water and do localized spraying to see if you can Isolate the area or when it is wet and the problem occurs try a drying agent like spraying WD 40 in the area to see if it goes away. The ECM is usually located inside the car so not likely to get wet. I did have a factory installed screw in the firewall rub through a wiring harness after several thousand miles and short out once on a Blazer, and a pin hole in a coolant line that when hot would squirt a few drops of coolant directly in the vent hole of the distributor shorting out the ignition on a Jeep so odd things do happen. All that to say don't assume anything can't happen!

 

[user 423]

I took it to my local mechanic shop, who have been pretty reliable at discovering electrical issues in the past..and they told me that it was charging fine, and they could find no issues with it.

 
So there were no codes?

Also, let me play this broken record again......check on a Chevy/Uplander forum for better info.

 

[abnorm]

How do you know your exact voltage when this occurs.....were is that connected ?

What does voltage have to do with your Power Steering?

What.......I say what is the connection between loosing power steering and alternator low voltage and DAMP ? Have you checked your Belts ?

 

[user 423]

^
Some vehicles evidently do have electonically controlled PS ( I was wondering,too).

Code P0636 (or others) show trouble in that area.

https://www.obd-codes.com/p0636

 

[JasonMcD]

This is correct. Also, i did check on the Chevy forums, and while there were a lot of questions pertaining to this issue, there were very few answers. 

The code was: co899 'voltage low'

I like the idea of using a spray bottle to isolate the possible area of issue. I happened to take another look at the battery cables and terminals, and they do seem to be a bit corroded. Not the terminals, but the cable is. I feel pretty confident replacing those first, just to troubleshoot the issue and rule that out.

 

[highdesertranger]

So do you or don't you have electronic controlled power steering?

Never replace parts that are not bad. A lot of times you end up replacing perfectly good parts with inferior parts.

Highdesertranger

 

[Scott3569]

I am assuming your alternator is included in your serpentine belt system.. Have you tried replacing the belt??

I mention this because you say it is only happening in the rain, which could mean your belt is slipping.. so it could be the belt has stretched or it could be the tensioner..