Hey all, been going to post an update since feb 1st when I got this job done. Seems like never enough hours in the day. Also the day I finished this it was still early in the day, so I went ahead and pulled the rear tire and hub to find out what the "little leak" was around the drum/backplate... well that quickly turned into its own thread... here's link if anyone wants to see that mess. Waiting on parts at the moment.
Hey everyone, working on my 1986 M1008. I just finished putting in a new fuel tank, sending unit, instrument panel flexiable circuit board, and other to finally get my fuel gauge working, as I had in another thread which I will be updating maybe later tonight. In any case, when I was under the...
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In any case, I did finally fix my fuel gauge problem. I ended up ordering a new flexiable circuit panel for the instrument cluster, as well as all new bulb holders, and a new fuel gauge. However, I ended up not needing the fuel gauge, so I'm planning on returning that. I was intending to get the truck out and drive it first before I returned it, but truck will be sitting in barn for at least another week.
But to my fuel gauge problem, I did run into some issues that I'll get too.
I tried to test the gauge by pulling the signal wire from the sending unit on the tank, without pulling the tank back down. I had just enough room between the bed and the truck cab to see and try to reach in there and work. I ended up using a long screw driver & prybar, and one of those 4 prong long flexiable push button grapeling tools, usually used for picking up small parts thats not magnetic. Anyway, got the wire off, got under the truck and pulled it back through the frame. Used a set of vise grips and a tiny screw driver to ground the wire to the truck frame. Turned on ignition, but the gauge did not move. Still sat at the 3'oclock position, instead of returning to empty as it should have. Anyway, I decided it must be the circuit panel and/or the fuel gauge, so I ended up ordering both as well as all new light bulb holders and the 3 clips that attack the fuel gauge to the ciruit panel.
After getting my parts in, I pulled the dash apart... again... and pulled the instrument cluster. As you can see, the circuit panel contacts are clean, but the internal wiring is pretty green, much more so than I remember from the last time I had this apart. So it was corroding internally and that is what caused my problems.
View attachment 890365
When I took the cluster apart, I found that my fuel gauge was a replacment unit. It had a date code of 2008. I also found that it does not use the "cermaic" resistors. Instead its just a peice of plastic that acts as a spacer where the oriringal resister would have been.
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View attachment 890367 I
I looked at the new gauge that I had just gotten, and it looks identical but had a date code of 2021.
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So I figured I would try just replaceing the circuit panel first. Here are the new and old compared.
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If anyone is interested, these are the leds that I replaced the old bulbs with back a year ago. They have worked perfectly, and are a
Great Improvement over the stock bulbs. I replaced
All the bulbs in the instrument cluster with these. I did not replace the glow plug "wait light" and the light next to it
(can't remember what it is right now) as those are different bulbs. But those are bright enough anyway.
View attachment 890370
In any case, when I got the base back together and plugged into the main harness, turned on the ignition and... the fuel gauge went straight to empty! Which is what it should have done since I still had the signal wire grounded to the frame.
BUT... after a few minuets I started thinking that something didn't look right. So I went back and turned on the ignition again, only to realize that MOST of my dash lights were Not working... only had 4x4 light (as the truck was in 4-wheel drive as we had a big snow here and I had driven it to town the day before) and the "seatbelt" light, and Only the Left Turnsignal light worked, the right one didn't do anything. So I thought great now what...
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For the next hour or so, I was going back and forth trying to figure out what happened. As all my lights was working before I had pulled the cluster out, just not the fuel gauge. Now the fuel gauge works and most of my lights don't.
So I started thinking the main plug wasn't making contact, or that it was "misaligned" with the new circuit panel. After going through the plug and not seeing any reason that it wouldn't make contact, and seeing marks on the copper contacts on the new circuit planel from the plug contacts
(as I had plugged and unplugged it multiple times at this point) I finally took the cluster back out, removed the new circuit panel, and reinstalled the old one. But even then it
still had the same problem, most of the lights were still out.
After going through everything I could think of... I finally pulled
ALL of the "new" bulb holders and reinstalled my old ones and
BAM it all lit up.
View attachment 890373
So I got to looking closly at these "new" bulb holders and found that the electrical contacts were flat against the plastic base. There was Zero "spring tension" to push the contact into the circuit board. So I went through and bent ALL of the contacts forward, then reinstalled all of them, and then they worked fine.
Hard to see, but the first photo on the left shows the flat contact in the new bulb holders. Photos 2 and 3 going to the right show how I bent the contacts "up".
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Just ridiculous to pay $26 for new bulb holders, only to have to fix them. I had done the exact same thing with my old bulb holders before, which I should have just kept and sent all of these back, but some of my old holders were broke and needed replaced.
**BTW anyone who is going to order bulb and/or bulb holder replacements... there are 14 bulbs in the instrument cluster... somehow I only managed to count 13 and that was how many holders I ordered, so I still ended up using one of my old one's.
In any case, the next morning I was able to finish putting the dash back together. And I fished my fuel signal wire back up through the frame to the top of the tank. Took a bit, but finally got it pressed and locked back down on the electrical stud on the sending unit. Turned the igntion and the gauge went to just above the full mark. Which is just fine for me, as I had just filled the tank when I had went to town.
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By the way that reminds me. Here's something for you experts on here. You know how I mentioned earlier in this thread, that after I had dropped the old fuel tank and when I looked inside it only
appeared to be half full, even though I had just "topped it off" just before I started this project
(as I wasn't planning on doing this project when I filled the tank).
Well, after I got the new tank installed, and was waiting for the circuit panel and other parts to arrive. We had a big snow and I drove this truck to town, which is only an 8 mile drive one way. While I was there, I figured I would try to "top off" the tank again just to see how much it would take. Well, it took
12 GALLONS. So I am figuring, with what little I had driven the truck since I had last "topped off" the tank, I am estimating the tank was
Only Holding about 10 gallon of fuel previously, even though it was "full" and visible in the fuel neck.
But how is this possible? What would stop the tank from taking more fuel with fuel visibly in the fuel neck, when the tank was only approx half full??
Now with the new tank installed, and adding 12 gallons of fuel to what I already had, it should be holding the full 20 gallons now. But I had no idea that I was only getting a "half a tank" before. Since the fuel gauge didnt' work, I just got used to topping the tank off until I could see the fuel in the fuel neck *Assuming* at that point I had a "full tank". Just glad I didn't take any long trips recently, or I would have thought I was getting really horrible fuel mileage
Anyway, thats Hopefully the end of my escapades to fix my fuel gauge, and the other issues I found along the way. Just wanted to post this update to post my end results. I hate reading all through a thread and then never find out the "end of the story"
Thanks for the help All! ![[thumbzup]](https://www.steelsoldiers.com/images/smilies/icon_smile_thumzup.gif "Thumbs Up [thumbzup]")
......Now on to fixing my rear hubs, bearings, brakes and etc.... but thats in the new thread.
P.S. Excuse my poor spelling, which usually is where I reverse the order of some letters in a word. I don't know why but my spell check stopped working. Have tried selecting both
"enhanced spell check" and
"basic spell check", but neither one works.
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Which is what it should have done since I still had the signal wire grounded to the frame.
