Could use some help - possible problem with charging system?

[MarshallSF]

Hi Guys,

Welp - had my first Airstream towing experience tonight.

I had been doing some minor repairs before putting the 290 into the storage lot. Yesterday I put all new belts on. As I was tensioning everything I noticed a small green wire that had pulled loose from a bundle of wires running across the top of the engine. I accidently tapped it against the block as I was tying it back in and got a nice big spark. I traced the wire back to a wire nut where it tied in with a heavier gauge pink/faded red wire leading back to the part shown in the attached photo.

Today when I went to drive the rig into storage my batteries were dead. I jumped it and got the engine started, but noticed that the voltage gauge was reading low (10-11V) where it had previously been pegged to 13-14v continuously. The engine was running but seemed rough. I idled out of the parking lot, but when I gave the engine gas, it sputtered and eventually died completely.

Good Sam towed me to a spot near my house (definitely worth the $$) but tomorrow I'll need to get the problem sorted out and hopefully get the rig off the street and into storage.

I'm thinking I may have fried a voltage regulator/alternator but am far from an expert on these things. Has anyone experienced something similar. Any advice on what to check first?

Any help is much appreciated.

Thanks guys,
Marshall

[MarshallSF]

Quick update - ended up doing an 'early upgrade' on most of the charging system. The PO had wired the chassis and coach battery banks in parallel (at the tray) and was running an underrated 85 AMP alternator. I added a new chassis battery, separated the battery banks, installed a new 105A CS130 and was back in business.

Does anyone know the best place to find documentation on the original charging setup? I'm thinking there may be other creative wiring surprises on this rig.

[woodja]

Boy you work quick Marshall,
Don't know that I can be of much help except that the photo was of a solenoid, possibly the one that allows you to push a button & momentarily
connect both house & start batteries.
Even with our '82 310, the manual we got with it is from a 280 and not much detail regarding electrical systems.
Lots of smart people out there to help--good luck, Pete

[HowieE]

If the engine was off when this happened it looks like you grounded out the battery side of the starter solenoid. That wire should have been fused but obviously it was not.

The first thing I would do is remove the ground wire on the battery and test for voltage on the battery. I don't think you could have gotten to the alternator but you may have shocked the battery and it may now have a bad cell.

When you put that wire back to what it supplies fuse it, to the wire size, as close to the solenoid as you can because if it grounds out again it would melt and might start a fire.

[MarshallSF]

Thanks woodja - the rig was parked on the street in San Francisco so the clock was definitely ticking.

Thanks for suggestion on it being a battery bank connection solenoid - I'll check that out.

[MarshallSF]

Thanks Howie - I'm thinking I'll probably need to redo everything from the battery up to this point. Will definitely take your advice on fusing.

[crazeevw]

Sad to say that you're just getting to the tip of the iceberg when it comes to Previous Owners questionable 'improvements'. Hope you're able to get your wiring issues resolved.

Do yourself a favor, never look behind the dashboard......

Good Luck, Derek

[bkahler]

Originally Posted by woodja

...the photo was of a solenoid, possibly the one that allows you to push a button & momentarily
connect both house & start batteries.

Actually I believe the solenoid in the picture is one used to control the starter solenoid that is located on the starter. At least that's what it's used for on the 345 that I dismantled and the 310 sitting in the driveway.

Brad

[MarshallSF]

Thanks Brad. I've got a half dozen connections coming off this solenoid - are these ignition-enabled accessories or something?

[HowieE]

Generally solenoid will have 2 larger wires on each of 2 terminals and a smaller wire on a third terminal.
Now that said in this case I suspect someone has used one of the larger terminals as a power pick up point. You should test the 2 larger terminals for voltage to ground. One should have voltage with the key off. The other will have voltage when. Olathe is applied to the third smaller terminal. That voltage on the third terminal may be when the ignition is on or there may be a separate switch controlling that solenoid. You will have to test with the ignition and if that is not what is controlling the solenoid look for another switch.

It can be hell to figure out what someone else has done.

The fact that there are several wires on one terminal leads me to think someone made a controlled power point

[garry]

You have one solenoid that lets you tie the house and chassis batteries together to assist in engine or generator start. This solenoid is for momentary use and is activated by a switch on the dash.
You may have another solenoid that acts as a battery isolator and allows the alternator to charge both the engine and house batteries as you drive down the road.

The converter does not normally charge the chassis battery and sometimes folks modify it so it will. I have a jumper so I can have the converter charge all batteries when in long term storage with a pink ribbon on the steering wheel to remind me to remove before starting.

[bkahler]

Originally Posted by MarshallSF

Thanks Brad. I've got a half dozen connections coming off this solenoid - are these ignition-enabled accessories or something?

Marshall, take a look at these three pages from the Chevrolet Motorhome Chassis Service Guide. They describe the relay in question, why it's there and some of the connections. The two motorhomes I described earlier have this setup.

Hope this helps,

Brad

P30-hot-start-1.pdf
P30-hot-start-2.pdf
P30-hot-start-3.pdf