2006 M1083A1 6x6 Start up problems.

[Chickenbone]

I went out to start my FMTV up a couple weeks ago. Switched on the power switches, everything on the dash started flashing on and off. With a clicking sound coming from behind the panel.

I did not have time to mess with it at the time. So I switched it off and planned to mess with it later. Now, when I switch on the power, nothing happens at all. No power to the dash or anything.

But, the batteries show that they have a charge.

When it was flashing a few weeks ago, I thought it might be a starter solanoid issue of some sort(I am not a mechanic. Shade tree at best). But now I don't know.

Thought I'd toss it out here before I started digging in and making matter worse.

Thanks,

CB...

 

[GeneralDisorder]

99% probability that your batteries are dead.

How did you test them and what were your readings?

 

[Mullaney]

I went out to start my FMTV up a couple weeks ago. Switched on the power switches, everything on the dash started flashing on and off. With a clicking sound coming from behind the panel.

I did not have time to mess with it at the time. So I switched it off and planned to mess with it later. Now, when I switch on the power, nothing happens at all. No power to the dash or anything.

But, the batteries show that they have a charge.

When it was flashing a few weeks ago, I thought it might be a starter solanoid issue of some sort(I am not a mechanic. Shade tree at best). But now I don't know.

Thought I'd toss it out here before I started digging in and making matter worse.

Thanks,

CB...

.
I have got to agree with @GeneralDisorder . Your batteries are dead - or almost. These trucks (a lot of them) have a phantom draw against your batteries. My M-1088 will crank after it sits for a week. If it sits for two weeks, it clicks and clacks and won't "go". After about 3 weeks maybe 4, you are going to have to charge each battery overnight.

If I crank it daily and make a lap around a long block (maybe 5 miles) then it charges in the green...

 

[Ronmar]

Flashing and clicking is a classic bad/high resistance connection symptom. Resistance resists current flow not voltage, so like a kink in a hose, you can have full voltage/ pressure everywhere in a circuit untill you try and pull current thru that resistance. Then the lower current flow causes voltage drop.

VOLTAGE IS NOT GOOD UNTILL IT MEASURES GOOD UNDER NOMINAL LOAD!

1. Do bats measure 12.6-12.8v each? If not, charge or replace.
2. While measuring that 12.6+ at the batts, turn on the switch/load. Do they still read near 12.6+? Significant drop at batts indicates a bad battery load test...
3. Measure voltage at power panel test points. Is it 12.6/25.2?
4. Does it read within 3% of the voltage measured at the batts when the ign/load is turned on? If not, bad connection between batts and power panel...

 

[Chickenbone]

99% probability that your batteries are dead.

How did you test them and what were your readings?

Tested with multimeter. Showed 12.4v.

I"m gonna pull them and charge them this weekend. See if that helps.

 

[Chickenbone]

Flashing and clicking is a classic bad/high resistance connection symptom. Resistance resists current flow not voltage, so like a kink in a hose, you can have full voltage/ pressure everywhere in a circuit untill you try and pull current thru that resistance. Then the lower current flow causes voltage drop.

VOLTAGE IS NOT GOOD UNTILL IT MEASURES GOOD UNDER NOMINAL LOAD!

1. Do bats measure 12.6-12.8v each? If not, charge or replace.
2. While measuring that 12.6+ at the batts, turn on the switch/load. Do they still read near 12.6+? Significant drop at batts indicates a bad battery load test...
3. Measure voltage at power panel test points. Is it 12.6/25.2?
4. Does it read within 3% of the voltage measured at the batts when the ign/load is turned on? If not, bad connection between batts and power panel...

I'm gonna pull the batts and test/charge them this weekend.

 

[GeneralDisorder]

Tested with multimeter. Showed 12.4v.

I"m gonna pull them and charge them this weekend. See if that helps.

12.6 to 12.8 is fully charged (exact voltage depends on chemistry). 12.4 is discharged. Multimeter doesn't load them so it really doesn't constitute much of a test. Also if they are still hooked together in the truck you may have batteries at different charge levels and you need a solid 25v at several hundred amps to run the starter, etc.

 

[coachgeo]

carefully pull all your relays and fuses...... wire brush approriately..... die electric grease them and return to home. better yet replace them all.

 

[Ronmar]

The usual area for a bad connection is at the polarity protection device/LBCD where the cab, battery and alt cables all meet, out in the weather…

 

[Chickenbone]

It was the batteries as a few people suggested. I took them out and put them on a charger. Put them back in and the ole girl fired right up. But the batteries don't hold a charge. Time for new batteries it looks like.

 

[Mullaney]

It was the batteries as a few people suggested. I took them out and put them on a charger. Put them back in and the ole girl fired right up. But the batteries don't hold a charge. Time for new batteries it looks like.

.
Glad to hear that you've resolved your problem!
Nothing like a new set of Bats to pump your sweetie back up...

 

[Ronmar]

If you haven't already done so, Now is an excellent time to drop to 2 batts... 2 is more than enough for the truck, and unless you drive it daily, 2 batts will get a better chance to reach full charge when you do drive it...

 

[aw113sgte]

If you haven't already done so, Now is an excellent time to drop to 2 batts... 2 is more than enough for the truck, and unless you drive it daily, 2 batts will get a better chance to reach full charge when you do drive it...

Not of you are in the north. Flooded lead acid, 2x could not start my truck on -12f. Agm might have been able to.

 

[Ronmar]

Thats why you throw heat at cold, not amp hours… for below zero, diesel coolant heater/arctic kit, and 2 batts would start it just fine… Or just use the russian method and start a fire under the engine