|
|
|
|
From EuroVan Update, Issue # 28, Sept 2002.www.VWupdate.comFuel/Temperature Gauge, Part III In the December 2001 Issue # 26, I included a note that I had started to bang my dash again. Yes, the fuel/ temperature gauge problem had returned for the third time. Since it was a low priority repair, I just did not get to it until now. I did receive an e-mail from Joe Fretz, Aurora, Colorado, that contained some promising information. (This will count as a tip earning a free issue!) It read: "I also redid the fuel/temp gauge fix about three times. After doing it twice, I suspected the problem was the weight of the metal heat sink. One small screw goes through the voltage regulator, through the heat sink, and into the plastic instrument case. I noted that the screw hole had small fracture lines and I suspected that the weight of the heat sink caused the plastic to fatigue and crack, the screw to loosen, and the three male prongs of the voltage stabilizer (VS) to vibrate loose in their receptacles. My solution was to use a micro-bolt in place of the screw, secured by a washer and nut on the back of the plastic instrument case. I even used LockTite on the threads. Thus, the fractured plastic was compressed by the bolt and the VS (hopefully) would not vibrate loose. So far, this third time fix has held for many months." While I did not think this was applicable to my problem, just maybe there was a problem with the heat sink. On my second repair, I had soldered the pins to the socket, so there was no way they could vibrate loose. In any case, the scenario above is very possible, so check to ensure that the screw is secure. I finally tackled the job and broke into the dash from memory this time. Fortunately, I remembered all the pitfalls that had tripped me in the past. I went ahead and broke it all the way down to the printed circuit board so I could examine everything in great detail. It did not take long to find some new cold solder joints. There were two of them on the end away from the VS. Apparently on my first repair, I had only fixed the joints nearest the VS. Then on the second repair, I only soldered the pins into the socket. This made the pins away from the VS hotter and I theorize that this is why they developed the cold solder joint. Probably the fresh gob of solder that I applied is all that will be necessary to keep this from happening again, but I wanted to attack the root cause if possible. I figured the heat sink must not be doing its job effectively. It is a piece of galvanized metal. I considered replacing it with Aluminum, but figured it would be hard to find something that would fit. I ended up going to Radio Shack for a tube of heat sink grease. A couple of drops of this applied to the surface of the VS where it touches the heat sink assures proper heat transfer. Perhaps this is all that is needed. In any case, I am confident that the repair will hold this time. To summarize the proper repair of the fuel/temp gauge problem, it is necessary to repair the solder joints on all six terminals of the socket for the VS and in addition, the pins of the VS must be soldered into the socket. The plastic on the socket must be cut away for this step as described in Issue # 22. (Also see Issue # 2 for the original article.) Here are some pictures of the VS and the pins, click to enlarge! Bottom View - Top View -
Special thanks to Windy Gregory for sending me this entire write up of his experiences with the gauge cluster. Regards, Roger Moore |
