M1009 with no lights but not blowing fuses...

[Osro]

I've had her for about 3 months with no problems and then out of nowhere all the lights just stop working. No dash, brake, turn, horn, or head lights. She runs great and both batteries are reading 12.4v cold.

I changed out all the fuses, but still have the problem. So I pulled out the multimeter, and at the fuse box, the 30a "main lights" fuse shows the following readings on the multimeter when I adjust the military light switch on the dash:

service lights - 7v
off -12v
blackout-0v

im pretty good with electrical, but those readings seem off to me. Regardless, even if those readings are normal I'm not sure what to test next. It seems weird to me that all these things stopped working without blowing a fuse...

Thanks in advance for for any help

 

[porkysplace]

[h=3]CUCV Helpful Threads[/h]In here is section on the headlights and threads on most issues with CUCV's

 

[Monkeyboyarmy]

Check the connection between the fuse and fuse socket. My DD goes dark every once and a while and I have to move the fuse to get the lights back on.

 

[Osro]

Check the connection between the fuse and fuse socket. My DD goes dark every once and a while and I have to move the fuse to get the lights back on.

I checked that while replacing all the fuses

 

[doghead]

You do know how to operate the blackout and service light switch correctly, right?

 

[Barney-the-Duece]

Check your grounds and connections. You might want to also check the wire harness/connection on the driver's side firewall. I have had this happen to me. While trying to track down the problem I moved this harness and the lights went back on. I tried cleaning all the connections but every now and then it must get jared and doesn't connect just right. Remember with CUCVs, if it electrical clean it and if it's rubber replace it!

 

[Osro]

You do know how to operate the blackout and service light switch correctly, right?

Right toggle switch pointed upward toward the "service lights" setting?

 

[doghead]

Light Switch. A pullout knob that turns on service lights, blackout markers, and blackout
drive light when switches (22) and (24) are in appropriate positions. It also controls
brightness of instrument panel lights. Brightness can be changed by turning knob
clockwise or counterclockwise.

Servica Lights/Blackout Toggle Switch. This toggle switch must be moved to “SERVICE
LIGHTS ON” before brake lights, hazard warning lights, or horn will operate. It must also
be used in conjunction with light switch (21) to turn on service lights or blackout markers.
Refer to paragraph 2-15 for operating instructions. Service lights/blackout toggle switch
should remain in "OFF" position when truck is not in use.

Blackout Drive Switch. This toggle switch must be moved to "BLACKOUT DRIVE LIGHT
ON” and released for blackout drive to work. This is a self-centering toggle and will not
stay in “ON” position. Refer to paragraph 2-15 for operating instructions

 

[Osro]

Light Switch. A pullout knob that turns on service lights, blackout markers, and blackout
drive light when switches (22) and (24) are in appropriate positions. It also controls
brightness of instrument panel lights. Brightness can be changed by turning knob
clockwise or counterclockwise.

Servica Lights/Blackout Toggle Switch. This toggle switch must be moved to “SERVICE
LIGHTS ON” before brake lights, hazard warning lights, or horn will operate. It must also
be used in conjunction with light switch (21) to turn on service lights or blackout markers.
Refer to paragraph 2-15 for operating instructions. Service lights/blackout toggle switch
should remain in "OFF" position when truck is not in use.

Blackout Drive Switch. This toggle switch must be moved to "BLACKOUT DRIVE LIGHT
ON” and released for blackout drive to work. This is a self-centering toggle and will not
stay in “ON” position. Refer to paragraph 2-15 for operating instructions

Yeah, thats my understanding as well, but thanks for the official instructions though.

So, I flip the right toggle switch to "service lights on" like I've been doing for the past 3 months and all of a sudden I get nothing. Whats so confusing for me is the aforementioned multimeter readings at the headlight fuse. I'm getting juice at the fuse panel, and the service light/blackout toggle is clearly connected to it based on the multimeter changes when I flip the switch. I'm just not sure where the disconnect could be given that information.

 

[Warthog]

More than likely it is a bad headlight fuse socket. Get a new 30amp fuse (good quality, not a cheap Asian version) and add a little solder to the fuse. Many times the fusebox terminals will expand and not make good contact with the fuse. By adding some solder it will help make better contact. Not saying this is your issue but a good starting point.

You have not told us anything about your truck. Is it stock? Has the electrical system been modified? Is it still 24v? etc

 

[Osro]

More than likely it is a bad headlight fuse socket. Get a new 30amp fuse (good quality, not a cheap Asian version) and add a little solder to the fuse. Many times the fusebox terminals will expand and not make good contact with the fuse. By adding some solder it will help make better contact. Not saying this is your issue but a good starting point.

You have not told us anything about your truck. Is it stock? Has the electrical system been modified? Is it still 24v? etc

Well, now that you mention it, there are a couple outstanding details:

• its had a 12v conversion
• The left prong on the "Main lights" or headlight fuse previously melted at the fuse box. Someone at some point went in and "fixed" this issue by connecting the red wire (which I have read connects to the left post of the headlight fuse) to the orange wire behind the fuse box via an inline fuse. I've tested this addition with a multimeter and I'm still getting 12v after the fuse in the added line AND 12v at the right prong of the headlight fuse on the fusebox. Based on the wiring diagrams I've seen and what you wrote in the headlight post, this sounds like we're getting the desired results.

 

[Osro]

Are there any instructions on removing the fuse box, or things to watch for when I do? I looked but haven't been able to find them anywhere.

I think I have isolated the problem to the "fix" that was previously made when the "MAIN LIGHTS"/headlights fuse blew, and I'd like to pull the fusebox off the firewall so I can see whats going on.