Originally Posted by Jesse4

First, what I forgot to mention in my first post is that you should try unplugging the speedometer and see if that solves the problem. If it doesn't, stop right here, there's no point in going further. If it does solve the problem, here's what he told me:

Gingerly pry up on the diode (as I wrote, it's yellow with a stripe on one end; about the size of a stick match head, except it's rectangular, like, say, a little tiny shoebox) and see if it's soldered. Mine wasn't and one end popped right up. He said to take it off (unsolder the other end) and tin both ends as well as the "pads" on the board where it was soldered. But, before doing any soldering, put a heat sink between the ends and the rest of the printed circuit board and use just enough hat to do the job. I put a heat sink on, just barely heated the ends, and went out to try my handiwork. Eureka, the truck started right up, ran smoothly, etc. BUT . . . no odometer reading; it was just blank.

I know this sounds far-fetched, but he said the heat travels along the printed circuit foil to the square integrated circuit chip (black, about one inch square with probably ten leads on each side) and loosens the solder just enough to where it won't make contact. I truly doubted this part, because I was fast and that board never got hot enough to do any damage. Besides, that IC chip is a couple of inches away. There's no way. But he said to fix it I needed to resolder the end leg on each side of the chip (that's eight total). I did two and tried it . . . nothing. Did the next two (the two nearest the diode) and, voila, there was my mileage reading back again. The guy knows his stuff.

So, if you're going to try this, do what you can to limit that heat to the diode, but if the odomete goes blank, resolder the end legs of the IC, starting with the ones nearest the diode. They're not easy to solder, as they are tiny and close together, so do two and then try it. Patience and a steady hand are necessary. Good luck. If this is confusing, send questions and I'll try to clarify, but my experience is limited to one! Good luck.

Originally Posted by odoboy

I am writing here to say a big thank you to Jesse4 who had an answer to the problem that has been driving me nuts for a while.
I have a 95 E150 Club Wagon and my speedometer kept bouncing around the true speed (bouncing a lot at high speeds) and my engine tended to stall or even stalled at low speeds going either in forward or reverse.
I first thought that a speed sensor is the issue but i have replaced the whole rear axle (because the old one was broken in two) and i was still having the issue. Also, my ABS worked fine during the issue. I thought it might be a transmission issue but the engine tended to stall even in neutral, if the car was moving a little bit.
So, following Jesse4's advice, i have taken my dashboard off, and unpluged the spedometer...and voila...the issue is completely gone, no more stalling or hesitation. So i noticed the problem is in the speedometer. I think the problem was that when the spedometer kept bouncing it was detecting sharp decelerations and probably was cutting the gas (either to help the abs or just for fuel economy while decelerating).
I have taken the spedometer out ( it was quite some work to get to it) and i have found the part that Jesse4 was talking about: It is the only yellow part on the board and it actually is located in the upper left corner when you are looking at the board. I would like to say that the part in question is actually a capacitor and without it, the speed signal is not filtered and that's where all the bouncing came from. That capacitor acta the same like a capacitor in a ac to dc converter, it cuts the spikes and smoothens the output.
I had to use a sottering iron (not a sottering gun , those are too hot) and i resottered the capacitor to the board and everything worked from the first try. Now there is no more hesitation and the spedometer does not bounce at all anymore. It's awesome.
I have taken some pictures but i don't know how to post them here.
If anyone needs a picture, don't hesitate, send me a message and i will email you the two pictures i have showing exactly what needs to be done.
The reason the capacitor came off is because humidity was allowed to enter in the cluster area. I think in Jesse4's case, the reason the ic pins had to be resottered is because they were almost loose (also because of humidity) and they came completely loose when handling the board. Heat wil definately not travel throguh the board for a few inches, at least not enough to make a sottering come lose.
On the side, my advice to you all 95 E150 owners, get a spray of wd40 and spray all the electrical contacts around the dash (hazard switch, windshield wiper/washer switch) and you will not have any more issues with humidity, at least not for a while.
Once again, Thanks Jesse4 for your saving idea.

Originally Posted by Jesse4

My solution is different from Colour's as my problem WAs in the speedometer. Here's what I have found out, thanks to a very helpful local speedometer repair shop. This guy diagnosed my problem over the phone and talked me through the repair. On the back of the printed circuit board of the speedometer, there is a small yellow diode soldered to the board, in the upper right corner. (It's the only yellow component on the board, as I recall). If this comes loose, it causes the symptoms you describe. If you want to try to re-solder it yourself reply back to this message and I'll relate to you what he told me about doing it. IT'S NOT AS EASY AS JUST RE-SOLDERING, SO DON'T JUST CRANK UP THE OLD SOLDERING IRON AND HAVE A GO AT IT. If you're not really good with a soldering iron, have a low-wattage iron and a good heat sink, I'd recommend taking it to a shop that can do it. But, he was right on the money and it solved my problems completely. The truck ran normally right after I soldered that diode back in place.

My ABS light will come on with braking once in a great while, I don't know why. Then it goes away and doesn't show up again for, say, a thousand miles or so. Curious . . .

Let me know if you're going to try this (or if you do it and the electronic odometer goes blank, write back and I'll tell you how to fix it).

Jesse