1992 Chevy Mallard Sprinter Electrical Problems

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joshtb86

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Joined
Sep 19, 2017
Posts
12
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
 
The fridge, lights, etc. run off the house battery, not the chassis battery. However, when you start the engine, the engine alternator supplies power to both house and chassis systems.

If by "AC utilities" you mean roof air conditioner, wall outlets, etc., then yes, you must have shore or genset power to operate those things. They require 120v power.
 
Gary RV_Wizard said:
The fridge, lights, etc. run off the house battery, not the chassis battery. However, when you start the engine, the engine alternator supplies power to both house and chassis systems.

If by "AC utilities" you mean roof air conditioner, wall outlets, etc., then yes, you must have shore or genset power to operate those things. They require 120v power.

thanks!

but when i turn on the house battery when the engine is off - none of the lights etc run. does that mean the batteries might be dead if the dc stuff only works with the engine on or power generator on?

also - the fridge i have only has options for auto and LP gas - i saw a 12 volt dc connector on the back but i am not sure if it was running when i turned on the engine - could that be a problem with the wiring?
 
House battery could be dead or simply disconnected. Motorhomes often have a house battery disconnect switch that puts the battery offline, e.g. for longer term storage.
 
also - the fridge i have only has options for auto and LP gas - i saw a 12 volt dc connector on the back

When it is in the AUTO mode, it will run on 120V AC if available, otherwise it will switch to LP. The other position is to force it to use LP even when plugged in. The fridge needs 12V DC for it's control board, so needs that 12V whether on AC or LP.
 
With the engine not running, and the RV not plugged in to shore power, put a volt meter on the house battery. My guess is it is connected but dead and you will see well below 12 volts.
 
thanks for the help everyone! house batteries dead - 11.82 v checked this AM

will have to replace

when charged - can they run the frdige on dc power? or just power the control system?
 
Depends on the fridge make and model. Some are 3 way (propane, 120V AC, 12V DC). Many (most?) are two way, Propane and 120V AC. They ALL require 12V for the control system. 12V operation, when available, is a power hog and most would recommend against using it.

When Auto is selected, the fridge will  automagically use 120V AC if/when it is detected as being available. If not detected, the fridge will default to propane operation. If Auto is not selected, the fridge will go directly to propane operation.
 
From your description you have a 120V AC/LP fridge, not one that will run on 12V DC.  The 12V for your unit is only for the control board, not for cooling. Stu has listed the details above.
 
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?
 
joshtb86 said:
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?


It wasn't designed like that. You have a problem either with the converter, circuit breaker , either 12v or 120 vac. You need to find the converter and see if you have power going to it and the voltage leaving it. If you have a Magnetec power panel let us know the model number. If it is brown and has both 120 circuit breakers and 12 v fuses, the converter is in the bottom of the unit. If you take the complete cover off of the panel you will see the converter, but BE CAREFUL there is 120 vac if you are plugged in or running the generator. You can test the voltage on the 12v side of the panel with out removal, it will be on the very right side near the fuses. Could be 2 terminals or three depending on what model you have. 

edit: Fixed missing close quote tag
 
If the batteries do not charge on Shore/Generator power but DO on Engine power.. ODDS are (And I stress ODDS) the converter is toast.. BUT. As I said ODDS.

I"ve also seen the circuit breaker trip
And on MY RV the converter is a plug in model.. Guess what happens.. I usually figure it out long about 3 am too boot.

And though I've not seen this.  I can imagine the rig being wired so the engine charges HOUSE batteries EVEN if the disconnect is in the "Disconnected" position.. Mine does not do that at least as far as I know it does not do that. But who knows without testing if yours does.

The first thing I'd check is the battery disconnect.  ($0.00 if that's it) Then the converter circuit breaker (Resetting is likewise free) then the converter Reverse Polarity fuses (Low cost) then the converter (Higher cost)

Best converter to use as replacement..... Progressive Dynamics

For a "Stand alone" box. 9200
For a combination power distribution panel converter (The electronics are behind the fuse/breaker panel) use the 4600

Dongles optional .. I have only pushed my dongle button on rare occasions  And I know how it works .:)
 
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?
 
joshtb86 said:
and even if when on shore/generator power, DC works but the batteries  do not charge, it  still could be the converter?
That again depends on the model of power panel you have. Certain Magnetec power panels contained the converter with 2 outputs. One supplied power to about 1/2 of the fuses and the charger portion charged the batteries and supplied power to the other fuses.

You keep asking questions without providing us any info on what you have. Hard to help you without knowing what you have.
 
Charlie 5320 said:
That again depends on the model of power panel you have. Certain Magnetec power panels contained the converter with 2 outputs. One supplied power to about 1/2 of the fuses and the charger portion charged the batteries and supplied power to the other fuses.

You keep asking questions without providing us any info on what you have. Hard to help you without knowing what you have.

yeah sorry im pretty new to this and i actually dont k now what i have... also the rv is at my in laws because i live in an apartment and wont be back for another2-3 days

will let you guys know the next time i investigate

thanks!!
 
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
 
1992 Chevy frame "Challenger".    I've had it a month now, an here's what I learned.  2 batteries mounted under the exterior "hood" if you will. Started the big V-8 (454), and had 13.6+ VDC at only one of those batteries.  The other battery read 11.2 and dropping.  I found a newly mounted "Off-On" switch under the drivers seat and selected the "On" position.  Both batteries now reading 13.5 volts.  Yours should have this switch also. It must be selected "ON" to charge both batteries from the engine alternator OR the charger/rectifier.  Hope this Helps! 
 
That "series 6300 power centre" sounds like a Magnetek unit, picture below. It would usually have a metal door and inside you will likely find both fuses (12V) and circuit breakers (120V). The converter is built into this unit behind the lower grilled door. It will NOT be under the dash but more likely in the end of a bench, side of the bed, under the fridge etc. This converter is a very old style single stage charger and you would really benefit with a retrofit  to a three stage charging system that can be easily installed using a kit that is readily available.

http://www.bestconverter.com/MagnetekParallax-630073008300-Upgrade-Kits_c_64.html

All those pictures you took are part of the trucks electrical system, not the coach
 

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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
 

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