M885 - How do I tell if this is 24v or 12v truck?

[ckoutlet]

Recently bought a 77 m885 with no alternator. Went to the local U-wrench it and got a 12.95 of some old van. 12 for a new belt and slapped it back together. The truck doesn't run on alternator, if I unhook the battery. When I take my multimeter it says 28v at the alternator. Any ideas? Voltage regulator? Where m885's made with 24v, could the 79 van that I wrench the alternator off had been 24v?

 

[Bob H]

Welcome to the forum! Not many out there for the M880 series trucks.
These trucks operate on 12v, single battery on drivers side 12v alternator on passenger side, if I recall correctly Dodges won't run without a battery
The M885's didn't come with 24v but if it did
the 24 v is only for the radio equipment and possibly slave cable, the generator which is rated at 28v mounts low on the driver side and charges two batteries which sit on the passenger side.

 

[ida34]

I was thinking the dodges had a regular 12 volt alt then the radio trucks had a separate 24 volt alt and batteries. I could very well be wrong but that is how I remember it.

 

[M725]

Re: RE: M885 - How do I tell if this is 24v or 12v truck?

I was thinking the dodges had a regular 12 volt alt then the radio trucks had a separate 24 volt alt and batteries. I could very well be wrong but that is how I remember it.

Your right, with the M880's, 24v was just for the radios only. Como trucks only had mounts for two alt.

 

[N1265]

RE: Re: RE: M885 - How do I tell if this is 24v or 12v truck

The ALT for the '79 Dodge van should be 12 volts.....

Are you trying to solve a specific electrical problem ? These trucks are noted for having electrical glitches....

remember, the voltage regulator on the firewall needs to be grounded....

 

[M725]

Recently bought a 77 m885 with no alternator. Went to the local U-wrench it and got a 12.95 of some old van. 12 for a new belt and slapped it back together. The truck doesn't run on alternator, if I unhook the battery. When I take my multimeter it says 28v at the alternator. Any ideas? Voltage regulator? Where m885's made with 24v, could the 79 van that I wrench the alternator off had been 24v?

You didn,t say if you have 1 or 2 batteries. All M880's are 12volt at the motor ( elec parts< starter, dis. lights) the military radios are 24 volt. Only way you can have 24 volts is you have 2 batteries wired for it with only one alt.