M1009 popping the main light fuse

[Okie Cowboy]

I'm having an electrical problem with my M1009. I keep popping the main light fuse. I've done search after search and tried cleaning and checking wires and such. I still have no lights and every time I replace the 30a fuse and flip the service light switch to on it pops the fuse. What am I missing or not doing to get this fixed. I'm willing to throw anything at it and hope something sticks any suggestions appreciated

 

[truck1]

Sounds like a dead short somewhere, or a bad switch. Check your sealed beam plugs. They heat up and have been known to crack and lose the plastic insulation . Also that stock setup is too much for the stock switch assembly. LMC and others sell an upgraded heavy duty front light harness with relays to ease up the load on the switch and circuit . It is an easy upgrade, pretty much plug and play. Google chevy truck heavy duty lite harness. Pretty cheap fix . Lots of threads here on SS regarding this subject. Good luck.

 

[ducer]

Check the big plug for your headlight and underhood harness where it comes out of the fuse block. It is on the LH sire of the firewall below the wiper motor (down low). You will need to remove the center bolt to pull the connector apart and check it for any signs of melting or overheating. I've seen this a lot.

Denny

 

[Okie Cowboy]

How do I check to see if the switch is bad? Would it be the blackout drive switch or headlight switch? I have no clue on how to check.

 

[Warthog]

Read the Headlight sticky (all of the stickies for that matter).

http://www.steelsoldiers.com/showthread.php?87544-CUCV-Headlight-Circuit

http://www.steelsoldiers.com/showthread.php?123199-CUCV-helpful-threads



It could even be an issue with your horn that is causing the problem.

Help us out here. What are your mechanical skills? Can you read a wiring diagram? Own a multimeter and know how to use it? These answers will help us guide you to fixing your issue.

 

[Okie Cowboy]

How do I check to see if I have a bad blackout or headlight switch? Where can I get one or can they be repaired? I'll check the headlight plugs and the under hood wire block today to see if I can get lucky. I thank everyone for the replies so far need my truck.

 

[Okie Cowboy]

I read the stickies disconnected the horn suppressor replaced relay and pulled fuse. My mechanical skill set is great for everything but electrical. I have a multi meter just got one have no clue on using it. I have trouble with the diagrams but try. I work best of KISS answers.

 

[Warthog]

The blacklight switches are a military item. Used is the only option that I am aware of. The headlight switch is a standard part and can be found in just about any parts house.

Have you found the FREE technical manuals that have all the wiring diagrams in them? They are listed under the Technical Manual link at the top of the page.

On a side note, the Oklahoma Convoy of Steel Soldiers will be participating in the Armed Forces Day Parade in Del City (OKC) this saturday. You are welcome to join us.

 

[Warthog]

With your limited skill set on electrical, it will take some time to work you thru the process but we can get it done.

Now to the issue.

Is you truck stock? Has the wiring been modified? Any additions added? Still 24v?

 

[Okie Cowboy]

My truck is still 12v - 24v hybrid the prior owner took great care of truck. I can park it without a drip pan. I don't see any major mods done. I have had the truck 5 months drove everyday no issues till now. If I can get some light I would love to bring the old girl to the parade she cleans up nice.

 

[Okie Cowboy]

I did find where a radio and solar charger were added but they are wired from battery through fused links not the fuse box best I can tell.

 

[Warthog]

Here is your first list of this to do.

Buy some good fuses. No cheap ones. You will be replacing them as they blow

We will be working our way backwards to find the cause. After each step try the headlight service switch

1 - disconnect the headlights
2 - disconnect the dimmer switch on top of the steering column
3 - remove the plastic trim from the dash
4 - unplug the headlight switch

 

[K9Vic]

......and underhood harness where it comes out of the fuse block. It is on the LH sire of the firewall below the wiper motor (down low). You will need to remove the center bolt to pull the connector apart and check it for any signs of melting or overheating. I've seen this a lot.

Denny

This is a good step, also when this is removed put a fuse back in and see if it blows. If it does you know the issue is on the inside of the cab, if it does not it is in the loom from the firewall to the headlights.

If the black out switch is bad you can test it, but kind of complex for me to explain the different ways to test it. The wiring diagram in the TM will show you how to bypass the switch using jumper wires on the plug. The blackout switch simply just turns on/off power to the lighting system (along with the black out lights). So jumping it at the plug will tell if the switch is good or bad.


Also, cut the diode on the horn relay as see here on page 5, post#43.
http://www.steelsoldiers.com/showth...light-fuse-melting/page5&highlight=horn+relay


If you are running high output silver star or replacement H4 headlights, your load is too high. You really should add the headlight relay harness that has been mentioned.

 

[K9Vic]

2 - disconnect the dimmer switch on top of the steering column

I had to sit there and think for a minute what you mean. The high/low beam switch under the dash on the steering column. Never thought of that being bad, but that could be it.

 

[Okie Cowboy]

Ok thanks I'll jump on this as soon as I get back from the Doc today. I think I can follow this thanks for keeping it simple. I am familiar with TMs I retired last year from the Army.

 

[Warthog]

. If I can get some light I would love to bring the old girl to the parade she cleans up nice.

http://www.steelsoldiers.com/showthread.php?121769-Del-City-OK-Armed-Forces-Parade-2014

 

[Warthog]

I was just thinking about this, If you split the firewall plug you kill all the power to inside the cab. Nothing will work. Go ahead and pull it apart, clean it with an old toothbrush and some electrical contact cleaner. Inspect for any corroded or broken tabs and put it back together.

 

[Okie Cowboy]

Ok I got as far as the horn diode. I'll cut it out in the morning still have fuses popping after everything I do.
I bought all new lights, relays, fuses, and switches today also got more contact cleaner and electric grease if I found it in a diagram I tried to get it to have on hand.
I'm ready for the next round of ideas I will not accept defeat!

 

[Okie Cowboy]

Ok so here is where I'm at as of now. I followed all directions cleaned everything again greased replaced all parts.
I took the service switch apart to clean it up found orange/black wire with insulation damage along with another I taped and tried it out lights work. I now have a new problem now marker light fuse is doing same thing. I have no clue checked bulbs they look good but the fuse goes when I hit the switch.

 

[Okie Cowboy]

So I guess another bad wire are there any parts that are common to go bad with the marker/parking lights that I should replace