1992 Chevy Mallard Sprinter Electrical Problems

[joshtb86]

Hello!

I purchased a 1992 Chevvy Mallard Sprinter used with 31k miles on it and noticed the following issue:

When I turn on the chassis battery, none of the chassis 12v utilities run (fridge, lights, fans).

If I run the motor and the alternator is on, the 12v chassis utilities operate.

None of the AC utilities operate unless it is plugged into a shore line or the AC generator is running.

I am brand new to RVs and do not really have an idea of where to start. Any help is appreciated.

Thanks!


This is the carfax info

1990 CHEVROLET P30
MOTORIZED HOME
7.4L V8 TBI OHV
GASOLINE
REAR WHEEL DRIVE

[Skip426]

Welcome to iRV2.

For openers I'm sorry but I have to correct your on some terms .

Chassis is the term used for the battery that starts the engine, and works the exterior lighting .
Coach or house is the battery that is used to operate the interior equipment in your RV. Interior lighting, furnace , fridge.

Have you found two sets of batteries , could be the coach batteries are missing or dead.
Your RV is of a vintage that wouldn't have an inverter , to power any 120 volt items , without being hooked to shore power or having the gen set running.
Do any interior lights work when the RV is hooked to shore power.

Some basic info on RV 12 volt systems at the site below.

The 12volt Side of Life (Part 1)

[joshtb86]

Originally Posted by Skip426

Welcome to iRV2.

For openers I'm sorry but I have to correct your on some terms .

Chassis is the term used for the battery that starts the engine, and works the exterior lighting .
Coach or house is the battery that is used to operate the interior equipment in your RV. Interior lighting, furnace , fridge.

Have you found two sets of batteries , could be the coach batteries are missing or dead.
Your RV is of a vintage that wouldn't have an inverter , to power any 120 volt items , without being hooked to shore power or having the gen set running.
Do any interior lights work when the RV is hooked to shore power.

Some basic info on RV 12 volt systems at the site below.

The 12volt Side of Life (Part 1)

Thanks!

So both house batteries are dead... volts were 11.82 on my voltimeter

Would this explain that the fridge won't run on 12 v power? Even when the alternator is on?

[Kiawah]

So both house batteries are dead... volts were 11.82 on my voltimeter

Would this explain that the fridge won't run on 12 v power? Even when the alternator is on?

Doubt it.

When you run your alternator, it 'should' be putting a higher voltage on the batteries, so you should see that 11.82 heading up to about 13.5 volts. If it is up, then you know that your alternator is putting out voltage, AND the charging process is making it's way to the house batteries.

Assuming you have a charger/converter which when you plug into shorepower it also charges your house batteries, you should see a similar effect. Turn engine off, voltage drops to battery voltage eventually. Plug in shorepower, charger will up the voltage to 13.5 ish to charge house batteries.

Get your battery situation fixed, and make sure you have verified both charging scenarios are working, and your batteries charged up. Then you can work on figuring out why devices are or are not working.

[MSHappyCampers]

Hi ! Welcome to IRV2! We're sure glad you joined the gang!

Congrats on the new rig! Sorry I can't really add anything to what the others have told you. Keep her between the ditches!

Good luck, happy trails, and God bless!

[joshtb86]

thanks for everyones help so far!

the batteries do NOT charge when i have AC power on either via shoreline or generator, only when the engine is on with the alternator running

then the batteries all have voltages of 13+

does this mean the charge converter is not working? or could this be how it was designed?

[mat]

Originally Posted by joshtb86

thanks for everyones help so far!

the batteries do NOT charge when i have AC power on either via shoreline or generator, only when the engine is on with the alternator running

then the batteries all have voltages of 13+

does this mean the charge converter is not working? or could this be how it was designed?

Likely the converter isn't working. Being that it converts 120v. to 12v. I'd be looking to see if a breaker is tripped. If not, than it's time to troubleshoot the converter itself.

[Soppy]

So just to keep things straight , you have one 12 volt chassis battery used for starting the engine and two 12 volt coach batteries used for running all the interior lights, water pump , vent fan ,etc. Check to be sure you have a 3 way fridge that will operate on 12 volts. Many fridges operate on propane or 120 volt shore power , but still require a 12 volt supply to operate.
Your first task is to find the converter and get it working.
You could also hook up a battery charger to the coach batteries and see if they take a charge.

[joshtb86]

thanks guys!

i have a 1990 chevy malard sprinter on a p30 chasis - any idea where to find the battery disconnect? or the converter? im not even sure where to start with finding them

and even if when on shore/generator power, DC works but the batteries do not charge, it still could be the converter?

[Skip426]

Originally Posted by joshtb86

and even if when on shore/generator power, DC works but the batteries do not charge, it still could be the converter?

So when you're on shore power , gen set or with engine running , the interior 12 volt items operate .
With the 12 volt operational on shore power , it sounds like the converter may be operational but something could be stopping charge from the converter getting to the batteries , as mentioned finding the converter for testing is in order .
Because they convert power from 120 to 12 volt , they usually hum, so maybe trying to track by sound would be possible ; and many look like the pictures below.

Average size would be 12" x 10 " x 4"

[Soppy]

Originally Posted by joshtb86

thanks guys!

i have a 1990 chevy malard sprinter on a p30 chasis - any idea where to find the battery disconnect? or the converter? im not even sure where to start with finding them

and even if when on shore/generator power, DC works but the batteries do not charge, it still could be the converter?

The converter could be located in one of the storage compartments or behind the fuse panel. The battery disconnect should be near the entrance door or on the dash. It could be labeled as coach , dc , 12 volt ,etc. Should be a toggle or rocker switch. The actual disconnect relay will be somewhere between the batteries and fuse panel.

[joshtb86]

okay so i took some pictures and video of all of the electrical things i found underneath the steering wheel.

https://photos.app.goo.gl/TQbpZwkDeODLpLz62

could any of these be the power converter? especially the one near the fuse box? to the left of it?


also found a manual for "series 6300a power center" if that helps

[Skip426]

Ok , the picture of the fuse panels .

Red arrow , is the chassis fuse panel , for items involved in the operation of the coach while driving.
The two yellow arrows are , coach fuse panels , for the items in the interior of the RV.
The large relays at the bottom of the lower panel , would be , coach battery disconnect and alternator charge interconnect .
Does the manual you found identify these items and give any testing info.

[joshtb86]

Originally Posted by Skip426

Ok , the picture of the fuse panels .

Red arrow , is the chassis fuse panel , for items involved in the operation of the coach while driving.
The two yellow arrows are , coach fuse panels , for the items in the interior of the RV.
The large relays at the bottom of the lower panel , would be , coach battery disconnect and alternator charge interconnect .
Does the manual you found identify these items and give any testing info.

okay - found the power converter

looks like everything is hooked up correctly

here is a link to a bunch of pictures and a video

any idea where to start? i read the instructions and everything looks like its connected correctly

https://photos.app.goo.gl/IZNgGkKzg1a2Hglm1