M1010 Interior Lighting Circuits

[lavarok]

So, in an effort to get my "surgical" dome light working in my M1010; I spent some time pouring over the circuit diagram in the back of my truck.

I need help from someone who has removed the interior panels and/or seen the insides of a M1010 box without the interior skin. I am trying to locate the splices and wire harness marked in red on the attached jpeg.

The "BO RELAY SW" is on the driver side fuse/power panel in the rear of the box. These splices and wire harness are somewhere behind the panels. I am guessing front driver side, but I'd rather KNOW and not guess since it will require drilling of several rivets to remove the panel.

My focus lights work, so I know its not a relay or lack of power issue. When I check for power at the front dome light switch, there is none. The dark blue wire should be 'hot'.

Help!

 

[SmokeyDod]

Just curious. How are you trying to turn on the "surgical light" (I assume this is the round blue light)???

 

[lavarok]

The "surgical" light is the fluorescent dome light. In the event of black out conditions, the blue light comes on instead of the "fluorescent" light.

I am using the dome light switches to try and activate the light. According to the circuit diagram, under normal lighting conditions when the focus lights are working, the blue wire to the switch should have power. In my case, my blue wire at the switch does not have power.

I have confirmed that when the black outs are activated, the focus lights will not work. In turn, the "fluorescent" light will not work and the blue light should work.

In my case, the "fluorescent" light doesnt work and the blue light doesnt work. Clearly, there is a wire connection issue since the focus lights work as expected.

Once I know where the wire splices are I will be able to trace the problem and fix it.

 

[SmokeyDod]

The reason I asked was that as you state --when you turn on the black out lights the blue light supposed to come on . Are you sure the bulb is not burned out? I have a 1010 that we drive and also another one with all drive train removed. - use it for storage.

 

[lavarok]

I'll need to check the blue bulb. However, I still need to find the splices to fix the dome light. You wouldn't happen to have an extra focus light you don't want?

 

[lavarok]

I was looking through the 34p and found this. It appears the wiring I am looking for is behind the side panel, probably behind the relay/fuse setup above the driver side wheel well.

I wish they had ran all the wires out to the relay/fuse panel. I don't know why anyone would put a wiring splice in such an unserviceable location. If the driver side bench was still installed in the truck; I would never be able to access the inside of the wall.

If anyone with an M1010 can take a photo of their relay/fuse panel, I'd appreciate it. I want to compare the wires I have visible on mine to yours. I am suspecting someone before me may have pushed the wires back into the wall. My dark blue wire from the BO RELAY leads back into the wall to the hidden splice.

 

[SmokeyDod]

Yes, I have extra one. Just send me PM and give me your address I'll send you one that I will make sure is working and I will see about taking some pic of panel under the benches (you say on drivers side of body in back?). Smokey

 

[lavarok]

Pm sent, thanks.

 

[lavarok]

My initial assessment of the circuit diagram was wrong.
The dark blue wire leads to ground and is not hot.

However, I did find in the process of analysis that when my fluorescent tube is installed the hot wire at the fixture does NOT read voltage. With the bulb removed, I get 12v. So the problem must be in the inverter circuit used to light the fluorescent.

I found a site that details such a circuit and I have removed the assembly so I can fix it.

12V Fluorescent Tube Inverters

Its actually a pretty ingenious design to take 12v and power the tube. After reading the above linked website, I see many more uses for this application.

Also, my blue blackout light works great now that I changed the burnt bulb. Almost got this M1010 at 100%

UPDATE: The "safety" resistor as detailed in the second diagram at the above link was bad. Given the use of it is not actually required, I removed the resistor and soldered a jumper across. I wired the inverter up for use on a bench, then added 12v and success! The inverter is working and lights the tube quick. Now I just need to reinstall in the truck. I have attached a photo of the back side of the inverter showing the solder points and the "GREEN" jumper wire. The board was covered in a plastic substance which I had to carefully scrape away to access the solder points for testing.