2020 Cascadia AC and voltage issues

While parked yesterday morning...

First issue I noticed was that my radio was off, meaning the stereo head unit - it normally always stays on as long as the truck is running. I pressed and held the power button and it came back on.

Next I noticed the AC was blowing but not cooling. I messed around with it, turning it up, etc. No change.

Got empty, drove 45 miles to Love's. Radio turned off a couple more times, always turned right back on when I pressed power.

Checked voltage on dash while driving - 11.1

Love's recommend changing AC compressor and all 4 batteries. Since AC compressor needed to be ordered, I opted for just the 4 new batteries. I had another delivery to get to.

Start driving, check voltage - 12.2. Called Love's, mechanic who did the work says reading should be between 12 and 13 while driving. Am I crazy or has normal reading been 13.6 or higher for as long as I've been driving?

Continued driving 200 miles to my next delivery and the voltage slowly dropped the whole time. 11.6 when I parked at midnight, now 11.4 at 3:30am

Afraid if I turn it off it won't start in the morning. Please help! Advice appreciated. Thank you

 

Forgot to mention - all 4 batteries were testing at 10.6 just before being replaced.

Alternator was tested after battery replacement. With truck running - 12.3

 

Check your grounds, there are a lot of them. We pay with a credit card so if we get some mechanic like this, we dispute the charges for labor based on the issue that he is not diagnosing the issue.

 

Your voltage should be 13.2-13.6 ish when driving.

You're losing accys because of low voltage.

Loves guys.... well, you know

I'd be checking the alternator wiring and voltage 1st

 

It should have been charging 13.5 after the battery change.

You have a charging issue

 

UPDATE

Voltage reading dropped to 9.7 around 5am, got a warning CPC Not Configured, turned truck off, turned power switch off

Got a local to come out for roadside, jump-started the truck, tested alternator - 10.0 and dropping

Replaced alternator, jump-started again, alternator now reading 12.9. However voltage reading on the dash is 12.3

Someone said "Check your grounds, there are a lot of them." I honestly don't even know what this means

Any ideas or suggestions?

 

YEP go to the dealer and get them to fix it. It sounds like a grounding problem, it takes both a ground through the chassis and engine to make the alternator work right. It could be a corroded end or a bad cable, for that matter that will cause the alternator's regulator to just see there is no need for voltage above what you are getting.

SO take it to the dealer.

 

Do you know if your truck has the aluminum battery cables. There was a recall you can google it or call Freightliner and see if your truck was already fix or affected. I had company truck doing funny electrical stuff they did not want fix it right away or look at it. Then going down the road one day the engine just cut off and they had to call tow truck. The repair was doing the recalled aluminum battery cables.

 

**** I forgot all about that, so here is the link ...

https://static.nhtsa.gov/odi/rcl/2021/RCMN-21V481-7216.pdf

 

Seems like if your batteries are dropping while you are sitting with everything off, then you have a short to ground. You can put a multimeter on batteries (main bus for fuses/ circuit breakers) and see if there is any current draw with everything turned off, then if there is start pulling fuses or flipping breakers one by one until you find the circuit responsible, then check that wiring. Disclaimer: This advice is worth what you paid for it because I don't really know crapola about truck repair.