headlight and horn, M1009 advice needed

ssdvc

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OK, in the last few weeks I have lost my horn and my fuel gauge (just reads hyper full), both at the same time. I also keep having a nagging problem with my passenger side headlight. It blew again this morning. I disassembled the headlight plug, checked it, cleaned it and reassembled. Looked over the wires (all seemed good) and checked to make sure the ground was GTG. hooked everything back up and when I turned on the switch, the light was dim, but not out. I then (finally) replaced the headlight switch and both lights were bright lights. WHOOPPPPEEEE!!! That is until this morning when that light went dim, then blew. What heck is going on???

Then, on top of that, over the last two weeks, my truck has been very hard to start. Fires off on the first turn of the key, but then dies. It takes about 4-5 5 second turns of the key to fire again. Once she catches, the idle surges for about 5 seconds, then smooths out. I have plenty of power once she starts and I have zero issues driving, passing or going up hills. It was only doing it in the morning, after sitting all night, but this afternoon when I got in it at work, she did the whole hard starting routine all over again. I did have a leak at the fuel filter and it was dripping on the ground. I did not get to it, but now there is no fuel leak evident any more. I am wondering if fuel is draining back into the tank as she as sitting for a period of time.

Just looking for some ideas. I would like to fix it before I travel in a few weeks on work related business.

Thanks !
 
293
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On the headlight problem I would take all the grounds loose and shine them up with sand paper or something; headlight grounds, block to frame, frame to cab. The running problem sounds like you are sucking air/ drain back problem and you might not see signs of a fuel leak to get the drain back. I think the OEM filters housings are a problem could be that.
 

ssdvc

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Thanks wrench turner. I checked a lot of the grounds and still have the headlight issue. I need to find the time to pull the headlight harness and check for shorts. Otherwise, what could be causing the headlight to blow (4th light since I got the truck).

Now I need to find out why the horn doesn't work (put a new one last week, no joy) and the fuel gauge is also TU.

As for the stock filter leaking, I may (Rick, don't hate me) go with a screw on unit that I bought for my other M1009 that I just sold.
 
293
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Location
Liberal Kansas
I know its kinda different but still the same. I had a 79 chev pickup with the right head light dim ( it did not burn them out but it was dim) the fix to it problem was to take apart and clean the ground they are right behind the head light once i did that i never had trouble again. Not sure about horn. It just a power and ground thing could be steering wheel not getting a good ground. Same with fuel guage
 

MarcusOReallyus

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I checked a lot of the grounds and still have the headlight issue.
What does, "checked" mean?

If you looked at them, you didn't accomplish anything. They need to be taken apart. They can look just fine and be very much not fine.

Check the Diode section of the Helpful Threads sticky. I think you'll find some useful info there.
 

Tinstar

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NOS GM CUCV headlight harness is available on eBay.
I bought one for a spare. Just FYI in case you need to go that route.

Agree on the grounds.
Physically remove and clean up each one and use electrical grease.
Just looking will do nothing.
Lots of sharp edges up front. Check and follow each wire to make sure nothing is shorting out.

I’m sure you’ve already checked the horn fuse, relay and grounds.
Have you used a voltmeter to see where the power to horn stops?

I had horn issue that was finally traced to turn signal switch.
Installed NOS one and been working great ever since.

Good luck!
 

sneekyeye

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I'd recommend reading these three threads about the headlights and fuses blowing in the headlight circuit. They are a good source on the issues you are having. On the idle surging, it sounds like you have a fuel leak getting air into the fuel filter since you found fuel leaking before. Is it the factory square style filter? Those are kind of notorious at this point for causing air in the lines. It may be sucking in air once you shut it off and the fuel slowly dribbles back into the tank. There is a check valve that you ought to check on the injector pump as well
Check valve thread
https://www.steelsoldiers.com/showthread.php?46001-m1008-surging-bad-injection-pump

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

CUCV Melting Headlight Fuse and Horn Circuit fix
https://www.steelsoldiers.com/showthread.php?104746-Why-is-my-headlight-fuse-melting

LMC Headlight Wiring Harness upgrade
https://www.steelsoldiers.com/showthread.php?124720-LMC-Truck-Head-light-circuit-mod
 
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ssdvc

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​​OK, Got to fixing the truck on Sunday. Here is what I got to.

Addressing the passenger side headlight being out/dim:
Before I started, I checked to see if the passenger side headlight was a bright light. No joy, headlight was 100% out. All other lights were functioning as they should. Did a quick voltage check at the headlight plug and I did have 12v when on. I also checked continuity on all grounds, GTG.

Once again, I removed the front battery, removed the frame and radiator support grounds, cleaned them with a wire wheel (they were very clean to begin with), removed the headlight connector, disassembled said connector, cleaned and "adjusted" all contacts, took apart the harness and checked for bad wires all the way over to the driver's side headlight harness. I didn't find anything out of the ordinary. Took a meter and also check for continuity. All good. I reassembled everything, and low and behold, I the passenger was a bright light and all other light were 100% too. I am thinking the cause was that either one of the 12V source wires or the ground wire was not making good contact with the bulb prongs. Don't really know what it was or how long this will last as this is not my first time doing all this, but I'll keep everyone posted.

Fuel Block:
So I had the time and decided to run the truck for a few minutes to see if I could locate the fuel problem, see any leaks, etc. Again, she took a bunch of cranking to get started, surged when she caught, then smoothed out and ran great. I then took her around the block, then parked her and opened up the hood to have a look, while still running. I was poking around under the hood and couldn't really see anything from a topside view, but I did notice some "wet" areas below the fuel block, towards the driver's side. I crawled underneath while she was still running (yeah, wheels chocked, parking brake on) and had a look. I noticed fuel was dripping, slowly, from the fuel block on to the left side of the engine.

So I shut everything down and went and pulled off the fuel filter, disconnected all lines from the block and pulled the block. I noticed that there was some dirt, like it had been leaking for a while, on the fuel filter side, and also on the back of the block, which was also soaked with fuel (not from spilled fuel either). I had purchased an FM100 setup from GimpyRob a while back for my other 1009 and so I installed it, filled the filter up with fuel, installed and then reconnected all the hoses. I fired her up and it only took 3 tries before she fired and kept running. Took her for a test drive and everything checked out and was completely dry. For sh*ts and grins I am going to try and rebuild the fuel block and keep it as a spare (for posterity).

A quick question. Of the two fuel lines (3/8 and 5/16 I think), the smaller diameter hose goes under the intake manifold. That hose is cracked and in rough shape. I am going to need to replace it and was wondering if I have to take the mainfoild off to do it? The larger hose just clamps to a fitting that is accessable from the top.


I still don't know what the deal is with either the horn or the fuel gauge not working, but I will try and get to them shortly. I love these trucks, you just need to have patience with them and turn a wrench or two every once in a while.
 
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Tinstar

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Your doing it right!
Tackle one thing at a time and do it right the first time.


As for the fuel hose under the manifold, I can’t answer that.
Mine had been replaced by the Military shortly before I bought Truck.
 

sneekyeye

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You don't have to take the manifold off to replace that hose if your clamps are reachable with screwdrivers or pliers or whatever. I didn't have to remove mine. But buy the best fuel rating you can find for fuel hose so you dont have to do it again. I used 30r9 rated hose. At least don't put the cheapest 30r6 rated hose you find at the parts store on the reel.
 
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MarcusOReallyus

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Your doing it right!
Tackle one thing at a time and do it right the first time.
Agreed!

As for the horn, the ground there might be suspect, or the horn itself. Take it off and connect it directly to 12v, and see what you get. The diaphragm can rust in place. Sometimes, repeatedly (like, dozens of times) hitting it with 12v can break the rust loose and give you a bit of sound. Once you get to that point, you just keep it up until the rust is all broken loose and the horn is working normally again.

If the horn itself is okay, I'll bet you'll find your answer in that horn sticky, linked above.
 

acthomp781

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I replaced the fuel hose underneath the intake by using a long 1/4 inch extension and a universal joint on the end. The air filer housing removed, and accessing the fuel hose clamp at the IP from the drivers side of the engine, going in between the intake manifold and the valve cover. Kind of tricky body position, you have to be leaning over the engine at an odd angle. I have medium sized hands and could get the hose pushed on the IP from the rear of the engine, under the intake manifold.
 

ssdvc

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HAPPY THANKSGIVING !!

OK, an update (finally) on this.

So I have been trouble shooting my horn issue for weeks. Traced the wiring, checked continuity on everything, installed new horn, new relay and snipped the did out. STILL NOTHING. So, last Sunday i took apart the horn button, cleaned the rust and made it look pretty, reassembled and still NOTHING ! So, I ordered the little plunger, plastic sleeve and spring combo from NAPA. The part came in Tuesday and after I got home this afternoon I swapped it out. Went to reassemble and as I was putting it together the horn beeped. Success !!! Well, sort of. Apparently the new spring is too long and as I tightened the three screws on the ring the horn would just keep sounding. I wound up taking the old spring and working it carefully to make it just a bit longer, and when I reinstalled the assembly, all worked as it should. I will see how long the old spring will last and I have a huge bag of springs I will go through to find a new one to replace it should the need arise.

Oh, I had to drive up to NH over the last few days and pick up my oldest son's garden tractor (an Ingersoll 220) and bring it down to CT so a CASE/INGERSOLL tractor "guru" I know could work his magic on it.

It was cold up there this morning and after the truck cycled through the glow plug cycle and the light went out, I fired her up. She spun freely (the new synthetic oil helped) but didn't start up. I cranked her again and after about 10-15 seconds of cranking, she had a hard time catching, but finally fired up. Lots of smoke (unburnt diesel), but she smoothed right out and all was good. She didn't do this last winter. Cause?

Now the only thing left is that **** fuel gauge. I am not as ambitious as CUCVRUS (I have no idea where he gets his energy from !), but I will get to it (at least the smaller stuff) as time permits.

I need to retire !!
 

ssdvc

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CT
Hi Rick,

Happy Thanksgiving !

Yup, that gauge is pegged hard over. It just did it one day. I was hoping it was an easy fix, but nothin seems easy these days.
 
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