alternator issue?

[travis8352]

i have a 1985 chevy m1008 cucv. its got 48000 miles and i bought it september 2015 and parked it for the winter. today i finally got it running after letting it sit all winter and i got it running and drove it around for a little bit fiddled with getting my brake lights and blinkers working and i shut it off and i tried to start it back up again and it barely turned over. not enough to start the engine so is this a bad alternator? i also do not have very powerful batteries powering this truck as the good batteries it had were stolen. the batteries it has are a 630 cca battery and a 550 cca battery which could cause this issue but when i started it up before it cranked over fine which leads me to believe its not recharging. so basically all im asking is it the batteries or the alternators? im replacing the batteries either way but would like to know if i should look into a new alternator as well. thanks

 

[cucvrus]

Does it have a volt meter? Do both Gen 1 and Gen 2 idiot lights illuminate when you turn the key on without the engine running? Are both fan belts in place and tight?

 

[travis8352]

Does it have a volt meter? Do both Gen 1 and Gen 2 idiot lights illuminate when you turn the key on without the engine running? Are both fan belts in place and tight?

only gen 2 light comes on. ill check on the fan belts tomorrow

 

[MarcusOReallyus]

Welcome!


It might be a bad alternator. It might not.

Have you downloaded the TMs yet? The troubleshooting guides are really good.

You should take some time to read the Helpful Threads sticky, too.

 

[travis8352]

Welcome!


It might be a bad alternator. It might not.

Have you downloaded the TMs yet? The troubleshooting guides are really good.

You should take some time to read the Helpful Threads sticky, too.

thanks. no i have not downloaded the TMs yet but i will take a look.

 

[cucvrus]

With the key in the on position engine NOT running. Reach up under the dash and wiggle the bulb socket in the cluster for Gen 1. That will NOT charge with the bulb not lighting. If you are in doubt. Switch the bulb with Gen 2 and see it is just the bulb. You can clean the contacts on the socket and back circuit board with a pencil eraser temporarily just to get the issue diagnosed. I hope that helps anytime just ask. Good Luck.

 

[howardc]

When the batteries are replaced and it starts, the voltmeter will help (if it works that is). Autozone or other shops can test for you as well. Hopefully it's just old under rated batts that the alts couldnt charge up. If it's one thing I've learned with my own electrical bugs, fully charged batteries are a must when troubleshooting.

Oh yeah, and download the TM's.

 

[Warthog]

The troubleshooting section of the tech manual says to make sure your batteries are full charged before starting any troubleshooting. It saves a lot of guess work.

I like to add load testing to that statement.

So make sure your batteries are fully charged AND load tested before starting any troubleshooting, expecially starting and electrical issues.

It may be the batteries and also time to rebuild your alternators. No need to be stranded somewhere with a truck with dead batteries.

 

[cucvrus]

I slave / jump start thru stone cold dead batteries on CUCV"s all the time. That does not seem to effect the ability of the truck to charge properly. It does help to have good batteries if I shut it off shortly jumping it and then try to restart it without assistance. I know most guys don't have 2 vehicles to start with so you are better off with new batteries. I use 2 vehicles in the very cold dead of winter. The slave cables are your best bet when it is very cold. I do not use my block heaters. But yes new batteries will be a big help. As low voltage weak batteries tend to ruin starters and starter relays. Good Luck. Have a great day.