Dead Deuce

[jimm1009]

Hello fellow 2.5 ton owners.
I drove my M35A2 the other day with no known issues.
I walked out to fire it up for some light work about a week later and
it was electrically dead. Immediately I though that the batteries were dead as the heater
switch was left on in the low position.
I opened the battery tray up and found two bad terminals so I replaced them but no joy.
I roll started it and it runs fine but there is no electrical system. I checked all the battery cables for damage and corrosion.
It is as if the master switch is turned off and there are no lights, no electrical gages that are powered, etc. I drove it about
three miles to where I needed to park it and nothing changed during the drive.
I am looking for ideas on something like a dead relay, etc.
I will have to fix it now as it can not be pull started where it is parked in the storage facility.
Note: I purchased a new front harness due to some other issues with the original harness
being from 1970. Have not replaced it yet due to some very severe changes in my life and
housing conditions, etc. but I hope to do it soon.

A 2nd issue that has been mentioned; I have the old brake light switch that quite often leaks
and fails, etc. I want to retrofit my truck with the newer style air switch.

Thank you in advance.

 

[Katavic918]

If your batteries are stone dead and you push start it, you may have overloaded you generator. Do you have charging voltage?

 

[jimm1009]

No I do not. That is why it looks similar to the master switch being turned off.
I need to look at the switch and connections and probably trace wiring back from switch
as a guess. I have the diagrams but since I have moved locally my stuff is a little scattered
right now.
jimm1009

 

[Barrman]

Check battery voltage. If you have good terminals at the battery, voltage at the battery and still nothing with any switch inside. Try removing all the ground wires, cleaning them and putting them back together.

If still nothing, check voltage at the starter motor. If present there, you can use a screw driver or even better. One of those remote control starter switch things most auto parts stores sell for around $20 to bypass the truck wiring and make the starter work. One lead on the big bolt at the back of the solenoid and one on the small connector.

I had the exact same thing happen to my 1971 M35A2 about 3 years ago. I got in to do something and all was dead. Since the on/off switch controls power to the starter button. I pulled that out after doing all the checks I wrote about first I discovered there was no power even to the on/off switch. I started tracing the wiring and found all power stopped at the firewall. My wires were corroded from the inside out.

I used the remote start option I also already wrote about to move the truck around until I had time to do a complete front harness swap. Now that is done and all is well.

 

[Jeepsinker]

#10 wire broken off at magnetic relay bolted to the block.

 

[Rmtaunton]

#10 wire broken off at magnetic relay bolted to the block.

Been there done that


Sent from my iPhone using Tapatalk

 

[marchplumber]

#10 wire broken off at magnetic relay bolted to the block.

That "knowledge" didn't come easy!! Appreciate it being shared though, THANKS!!

 

[Jeepsinker]

I have a whole video series on installing new wiring harnesses in the M35A2. I have become intimate with the wiring on these trucks.

 

[jimm1009]

Hey Jeepsinker.

I am sure that others including myself would love to see those videos.
Is there a way to do so as I would really like to see them soon.
I have a weekend or so of tinkering to do starting at 14:30 Eastern today.

jimm1009
1984 M1009
1970 M35A2
1951 M38
1946 CJ2A

 

[Oerthedge21]

He has a YouTube channel, just search Tactical Repair on there and you'll find it, dudes got loads of incredibly useful information there

 

[Jeepsinker]

https://www.youtube.com/playlist?list=PLp1oqEXZZEvDTSW99TW7Ar-Hxnx32qLgz

 

[Jeepsinker]

https://www.youtube.com/channel/UC_6OEBrY6vNe4HK4CCpO21w

 

[Jeepsinker]

And also, check your ground wire from your batteries where it connects to the frame. The terminals like to break off right at the frame and you can't see it unless you pull the battery box out.

 

[jimm1009]

Well Katavic918 had it correct.
I could not find my voltmeter so I put a 12 volt LED bulb on one battery at a time.
They were so stone cold dead that the would not illuminate a single mall bulb.

I took out the three year old batteries with a two warranty and turned them in for some
new batteries that had a five year warranty and the beast roared to life!
I was lucky as the alternator did not take a hit and works just fine. I let it run for about 20 minutes at about
1200 rms once it warmed up. All is well once again. Now I just need to replace that original style brake switch with
the new air powered one and change my front harness and then fix the turn signals.
jimm1009

 

[Jeepsinker]

https://youtu.be/62enPuSln1k

 

[Katavic918]

Well Katavic918 had it correct.
I could not find my voltmeter so I put a 12 volt LED bulb on one battery at a time.
They were so stone cold dead that the would not illuminate a single mall bulb.

I took out the three year old batteries with a two warranty and turned them in for some
new batteries that had a five year warranty and the beast roared to life!
I was lucky as the alternator did not take a hit and works just fine. I let it run for about 20 minutes at about
1200 rms once it warmed up. All is well once again. Now I just need to replace that original style brake switch with
the new air powered one and change my front harness and then fix the turn signals.
jimm1009

That made me think of something. Since you push started it you didn't have the exciter voltage necessary to turn the generator on in the first place. If you had jumpstarted it the generator would have started charging. Oh well once batteries have been discharged that bad it's best to replace anyway. Glad you got it figured out.

 

[jimm1009]

Correct. Since they were 99.9% flat there was not enough to make the alternator work.
An older generator would have started charging immediately.

Any way, back on the path to recovery now.

 

[jimm1009]

Not sure why that window popped up but I was using my work 'puter at the time.
Sorry.
jimm1009

 

[frank8003]

Hello fellow 2.5 ton owners.
I drove my M35A2 the other day with no known issues ~ Have not replaced it yet due to some very severe changes in my life and housing conditions, etc. but I hope to do it soon.

A 2nd issue that has been mentioned; I have the old brake light switch that quite often leaks
and fails, etc. I want to retrofit my truck with the newer style air switch.
Thank you in advance.

Been posted before to help

Do you need all the PS postings?

 

[The Green Tomato]

HAY That's just what I am going through right now! Thank you for posting this problem. Your right, no power what so ever. I traced and cleaned my grounds like suggested with no change. Have a new Magnetic Relay ordered, I'm hoping this is the problem, if not I will be visiting those videos on wiring my self! Good luck keep us posted.