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REO not charging

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Good evening chaps


Im looking at a friends REO which isnt charging. Im a mechanic by trade, but am unfamiliar with its 24v system. Hoping someone here may be able to help :)


Basicaly its not charging the battery. Apparently it used to work, but one day stopped working. Its had a new regulator, and the alternator has been bench tested(not by me) and given a clean bill of health


i took a photo of the alternator and labeled it -




1 is a good earth

2 is 24v battery feed

3 is a 24v feed to alternator

4 goes to the rear interior lights. 0v on it

5 is a broken black wire also going to the rear interior light. its niether live or earth, and has apparently never been connected.


Theres no voltage at any of the 3 regulator terminals at any time.


anyone got any ideas?

cheers, rich

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The TMs are very straight forward for testing. That is not the same alt I have.... M35a2s have been around for 40 years and have all sorts of different hardware on them. That looks like an earlier unit. The later high amp units do not have connectors on the top.


Grounds are STILL A HUGE ISSUE on M35s. So make sure you are down to bare metal and use a dialectic grease.


Are you sure that is the right regulator? Like I said the data plate on the truck is of little value.... I cannot order parts for my 66 buy just saying I have a 66 M35a2. You have to order for the right assembly you are repairing.


Your alternator does not look like a stock unit. Its not the 100amp high output, nor the stock 60 amp, and not the very old 25 amp unit.


What do the tags on it say? Get me a part number and I can get you a TM.

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