M1088a1 Camper Build!

[LongsPeakMoto]

Hello everyone hope this is the right form!! This is my second post so please bear with me.

I recently purchased a 99 m1088a1 that I am turning into a camper. I have a few problems I'm trying to figure out and hope to get some help. The first problem I am having is my blinkers are intermittent. Sometime I start up and turn my lights on and drive, only to have no turn signals and no hazards. Other times I do the exact same thing and magically they work, completely normal. I have tried resetting the "fuse" with no luck and even turned the car off and back on with no luck. It really is a hit or miss on if they will work or not.


My second problem is almost all the lower dash lights are lit up and won't turn off. This includes the ctis overspeed, dump lift, abs, and the blinker lights to name a few. The previous owner said it was one of the transistors on the lower right side of the circuit board. (I have not replaced it yet because I was wondering if this even made sense as a possible solution to the problem) *I put a photo of the dash below. The parking brake light does shut off its the bottom row that stays on.


My third problem; that scared the crap out of me the other day, was my ABS not turning on. It was raining a few days ago and as I was coming up to a yellow light, all my tires locked up and the truck started turning sideways. luckily I used to drive a 26ft RV up the rocky mountains weekly in the middle of winter and was able to counter steer and control the truck. This issue tho has me a little more concerned for winter driving tho. (Not sure if this has anything to do with my second issue though)


Thank you for the help! If I am on the wrong form please let me know so I can switch it over.

 

[Guyfang]

I moved your thread to the right forum.

 

[Mullaney]

Hello everyone hope this is the right form!! This is my second post so please bear with me.

I recently purchased a 99 m1088a1 that I am turning into a camper. I have a few problems I'm trying to figure out and hope to get some help. The first problem I am having is my blinkers are intermittent. Sometime I start up and turn my lights on and drive, only to have no turn signals and no hazards. Other times I do the exact same thing and magically they work, completely normal. I have tried resetting the "fuse" with no luck and even turned the car off and back on with no luck. It really is a hit or miss on if they will work or not.


My second problem is almost all the lower dash lights are lit up and won't turn off. This includes the ctis overspeed, dump lift, abs, and the blinker lights to name a few. The previous owner said it was one of the transistors on the lower right side of the circuit board. (I have not replaced it yet because I was wondering if this even made sense as a possible solution to the problem) *I put a photo of the dash below. The parking brake light does shut off its the bottom row that stays on.


My third problem; that scared the crap out of me the other day, was my ABS not turning on. It was raining a few days ago and as I was coming up to a yellow light, all my tires locked up and the truck started turning sideways. luckily I used to drive a 26ft RV up the rocky mountains weekly in the middle of winter and was able to counter steer and control the truck. This issue tho has me a little more concerned for winter driving tho. (Not sure if this has anything to do with my second issue though)


Thank you for the help! If I am on the wrong form please let me know so I can switch it over.

.
I would suggest that you have had a truck that an 18 year old drove and left the windows down in the rain. And that hole in the top of the cab leaked or is leaking. These trucks are amazingly tough, but years of just sitting there on the dead line most likely didn't help much either...

If you get yourself a toothbrush and a tube of antioxidation paste, sit in the right seat and spend most of a day cleaning the contacts on and under the fuse panel - I would guess that a lot of your wonky wiring problems will clear up.

While the batteries are disconnected, look under your spare tire. There is a PPD box that could use your attention too. Clean it like you care.



BE SMART and disconnect the batteries before you start cleaning. Use some AntiOx those battery connections when you connect the batteries back up. Then let's see if we can clear up whatever else needs attention...

Deoxit D5 is a spray can antioxident. If you don't disconnect the batteries, your truck may burn to the ground. You were warned...

.

 

[LongsPeakMoto]

I moved your thread to the right forum.

Thank you!

 

[LongsPeakMoto]

.
I would suggest that you have had a truck that an 18 year old drove and left the windows down in the rain. And that hole in the top of the cab leaked or is leaking. These trucks are amazingly tough, but years of just sitting there on the dead line most likely didn't help much either...

If you get yourself a toothbrush and a tube of antioxidation paste, sit in the right seat and spend most of a day cleaning the contacts on and under the fuse panel - I would guess that a lot of your wonky wiring problems will clear up.

While the batteries are disconnected, look under your spare tire. There is a PPD box that could use your attention too. Clean it like you care.

View attachment 904552

BE SMART and disconnect the batteries before you start cleaning. Use some AntiOx those battery connections when you connect the batteries back up. Then let's see if we can clear up whatever else needs attention...

.

Well the turret hatch definitely leaks haha its been on my to do list. I will say for a truck that's over 20 years old and got driven by 19 year olds who were cracked out on no sleep and energy drinks. It is a very nice looking truck. I mean it has its bumps and bruises but it still makes me happy with my choices. I am taking the truck to get welded today so when it comes back I will get in there and see if scrubbing it down helps at all. Thank you!

 

[Mullaney]

Well the turret hatch definitely leaks haha its been on my to do list. I will say for a truck that's over 20 years old and got driven by 19 year olds who were cracked out on no sleep and energy drinks. It is a very nice looking truck. I mean it has its bumps and bruises but it still makes me happy with my choices. I am taking the truck to get welded today so when it comes back I will get in there and see if scrubbing it down helps at all. Thank you!

.
What amazes me about these M10xX trucks is how PERFECTLY the turret leak drops the water squarely into your lap. Not on your shoulder, not on your leg, but squarely in your lap.



I sealed my M1088 and my M1089 and YES, it sure is nice to have a dry cab!

 

[LongsPeakMoto]

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What amazes me about these M10xX trucks is how PERFECTLY the turret leak drops the water squarely into your lap. Not on your shoulder, not on your leg, but squarely in your lap.

View attachment 904562

I sealed my M1088 and my M1089 and YES, it sure is nice to have a dry cab!

The previous owner said he resealed it and was on top with a hose spraying it all with no leaks. So I was super excited to not have to deal with that. Then the first time it rains it's a full on hurricane in the cab!

 

[GeneralDisorder]

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What amazes me about these M10xX trucks is how PERFECTLY the turret leak drops the water squarely into your lap. Not on your shoulder, not on your leg, but squarely in your lap.

Mine leaked square on my head and down my back.

Fixed with a gen one HIMARS hatch. They are SEALED once installed. Almost had to destroy the HIMARS cab to get it to give it to me.

The factory turret covers are specifically not sealed well so a turret can be easily installed. You can basically pry them off with your bare hands.

 

[Ronmar]

I do not think the idiot light issue is a transistor. Because of the way the lights are activated, some by a path to ground, and some by a supplied voltage, The lamp test circuit on the A1 panel is divided into two parts. One part that receives a ground to activate and one part that receives voltage to activate. The lamp test switch is a double pole switch one half providing a ground for test and the other pole a dc voltage for test. Those 8 lights have one thing in common, they all receive DC power from the lamp test switch, so I suspect either the switch or wiring is shorted, or the switch was replaced at some point with the wrong type.

What happens when you toggle the lamp test switch(upper left dash). If those lights go out and all the other lights go on, then the switch is incorrect, if nothing happens try the adjacent switches. The plugs are the same but the switches have different internal configurations, and if the fording switch and the lamp test switch plugs got swapped behind the dash, this might occur…

The hazard switch bypasses most of the other wiring, but it is also the power source for the flasher module. So it could be the connections around the hazard switch, or the module itself, which is under the passenger dash. Mine was bad, I replaced it with a solid state 3wire commercial unit made by Grote, about $30…

 

[Guyfang]

There are warning in the TM about welding on the truck. Precautions needed to be taken to ensure nothing gets damaged. Probably disconnect the batteries, hook the ground to the truck as near to where the welding takes place are at the top of the list. I am not a truck guy, but I seem to remember reading that in the FMTV TM. So DO look.

 

[LongsPeakMoto]

Sorry for such a late post to everything. Over the last couple months I have been going ham to turn this truck into a badass camper. I got the frame extended 4 feet at the back. (This does reduce my departure angle to about 25°, I am working to increase that hopefully by 5-10°)

After I got the frame extended I went to work on removing everything I could from the back of the truck. This included the spare tire, tire lift, air intake, 5th wheel hitch, and so much more. Once all that was removed I brought it back to the shop where we had to use a crane to pull my box off my other box truck. The first hope was with forklifts but found out quickly we needed a crane. When the box was removed we had to cut the floor so it would fit over the transmission. While I was getting covered in fiberglass we welded a bracket to mount our secondary transmission cooler to the side of the truck infront of the middle tire. A thick peice of medal now blocks the radiator from getting smashed to peices by rocks thrown from the tires.

Finally we were ready to put the box on the truck. Within the hour the box was in place and brackets were made to hold the box to the frame. Today I took it home with a lot more work to be done.

There is a bunch I need to do before it's ready but today was a bug step in the right direction. I need to now build a new floor that covers the transmission. As well as I need to find a way to cut some weight. I originally wanted this box as it has 3-4 inches of insulation on all the walls floor and roof. This helps a lot to keep the temperature easy to manage. Sadly tho this meant more weight then I originally wanted. My plan is to cut the back at a 45° angle and replace 50% of this box with aluminum and some thinner/lighter insulation. I know that is a huge step back and in hindsight I would have definitely made my own box or gotten a much much lighter one. Eitherway I am excited and can't wait to keep pushing this project farther and farther hopefully one day I can make it the dream truck I have been wanting. Let me know if you guys have any ideas for this truck!! BTW still never figured out my electric issues but I'm going to push that for a later date.

 

[LongsPeakMoto]

I moved your thread to the right forum.

I have slightly changed the objective of this thread to be more of me showing what I am doing plus if people have any tips or advice. Can you help me make sure this is in the right place. Or should I create a new form?

 

[GeneralDisorder]

What did you for isolation between the box and frame? With the frame that long there's going to be some flex and you don't want to destroy the box.

 

[Third From Texas]

I have slightly changed the objective of this thread to be more of me showing what I am doing plus if people have any tips or advice. Can you help me make sure this is in the right place. Or should I create a new form?

You'll get more visibility here for general troubleshooting questions.

As far as the camper build, you might want to make a dedicated build thread over in the Camper Conversion forum here on SS.
But there's no rule against it being in here. It's your choice.

 

[Guyfang]

If you want, I can transfer it to the Camper conversion thread. You tell me what you want, and we can do that. With the title as it is, I think it would be a good move to make.

 

[hike]

What did you for isolation between the box and frame? With the frame that long there's going to be some flex and you don't want to destroy the box.

It doesn't look like there is much clearance between the habitat and the rear tires. Is there enough up travel articulation for traveling uneven surfaces?

 

[chucky]

Just a thought but you should put a flat piece of 3/16th thick aluminum sheet metal from your habitat down past the bottom of that radiator or you wont make it a day before those tires throw a rock through the radiator ! Keep up the good work !

 

[chucky]

It doesn't look like there is much clearance between the habitat and the rear tires. Is there enough up travel articulation for traveling uneven surfaces?

I base my thought on the mfg putting the bed on a 1083 13 inches above the tread just for clearance issues but he may have wheel tubs under there i cant see !

 

[GeneralDisorder]

It doesn't look like there is much clearance between the habitat and the rear tires. Is there enough up travel articulation for traveling uneven surfaces?

I base my thought on the mfg putting the bed on a 1083 13 inches above the tread just for clearance issues but he may have wheel tubs under there i cant see !

Yeah doesn't look like there's any habitat suspension or articulation capability. Looks like any off-road would destroy the house in short order.

Aux cooler would be better between the frame rails with fans that push air into the low pressure area under the truck (ground effect).

 

[LongsPeakMoto]

If you want, I can transfer it to the Camper conversion thread. You tell me what you want, and we can do that. With the title as it is, I think it would be a good move to make.

If you could that would be amazing!