I had the dreaded burned out light problem at several places on my gage cluster. To replace the bulbs the cluster has to be removed from the dash, the clear lens taken off, the gage needles removed from the stepper motors using a regular table fork, remove the gage markings plate, before you get to the bulbs. Then, you find out that the bulbs are soldered to the PC board. So, I unsoldered the bad bulbs and replaced them with bulbs from Radio Shack. That worked ok but later I found out that the RS bulbs are not quite as bright as the originals, but oh well. (I didn't find the better bulbs till I did a search and found cluster rebuilders that sell the same brilliance of bulb. I'll buy them instead if I have to replace others.)
Anyway, I took note of the needle positions and match marked the needles to a piece of painters tape applied to the gage markings plate. After replacing the bulbs I aligned the needles with the match marks as best I could. A later test drive revealed that the speedometer showed that the speed is 2 mph too slow, using GPS as a standard. Looking into the subject of calibration, I found and bought a used Kent-Moore J33431-B signal generator that will calibrate all the gages in the cluster. It came with usage directions but they are kinda sketchy. I downloaded Mooseman's service guides, and the guide on 02~05 TB's, section "Gages", is really helpful. It takes a little hunting to identify connectors 1 and 2 on the PCM but with lots of cross-referencing between the guides, it can be done and the various gage wires identified.
The problem is I want to be sure I set the switches on the signal generator correctly before applying a signal to the speedometer circuit (I don't want to fry the electronics on the PC board) so that I can reset the needle positions. I know this is a rather technical question on the electrical side of things but if anyone knows how to properly set-up the generator, and with what Kent Moore wire harness connectors to use, please let me know. Kent Moore's website, gmspecialservicetools.spx.com, has the generator but lacks instructions on how to use it. I figured anyone with direct experience would know best. Thanks.
Anyway, I took note of the needle positions and match marked the needles to a piece of painters tape applied to the gage markings plate. After replacing the bulbs I aligned the needles with the match marks as best I could. A later test drive revealed that the speedometer showed that the speed is 2 mph too slow, using GPS as a standard. Looking into the subject of calibration, I found and bought a used Kent-Moore J33431-B signal generator that will calibrate all the gages in the cluster. It came with usage directions but they are kinda sketchy. I downloaded Mooseman's service guides, and the guide on 02~05 TB's, section "Gages", is really helpful. It takes a little hunting to identify connectors 1 and 2 on the PCM but with lots of cross-referencing between the guides, it can be done and the various gage wires identified.
The problem is I want to be sure I set the switches on the signal generator correctly before applying a signal to the speedometer circuit (I don't want to fry the electronics on the PC board) so that I can reset the needle positions. I know this is a rather technical question on the electrical side of things but if anyone knows how to properly set-up the generator, and with what Kent Moore wire harness connectors to use, please let me know. Kent Moore's website, gmspecialservicetools.spx.com, has the generator but lacks instructions on how to use it. I figured anyone with direct experience would know best. Thanks.