QuestionQUESTION: The speedometer on my 1991 Sundance does not work. The other gauges, including the tach all seem to work OK. Any suggestions? And while you're at it, how do I remove the cluster? I have it unscrewed but I don't know how to remove the connectors and I don't want to damage anything.
Thanks
Kirt
ANSWER: Hi Kirt,
Probably the distance sensor has been damaged, which can happen if the right side half-shaft is pulled from the transaxle extension housing without first removing it (such as when the cv boot/joint has to be replaced). It is mounted on the top of that housing (follow the wires that are running behind the engine from the driver side downward toward the transaxle). If the gear on the end is bad you may be able to just replace that. The sensor is held into the trans with a single bolt (10mm head, I believe) so just remove that and the connector and pull it out for inspection. The orange/white wire goes to the cluster (pin L of the red plug) if you want to check the continuity. The other wire is a common sensor ground.
On the cluster, if you have the auto trans you need to disconnect the mechanical connection to the prndl from the shift lever, etc. and the lower and upper steering column covers. But check to see if the problem isn't your distance sensor's pinion gear before doing all that. It would be better to xerox copy and mail the pages than to describe how the cluster is done. Use the "thank and rate" tab to let me know what happens, in the "comments" area.
Roland
Hi Kirt,
Although the sender may look OK, I would still test it electrically by putting an ohmmeter across its terminals and then rotate the right front wheel by hand (after jacking it up) to verify that you are getting 8 pulses in the resistance for every full rotation of the wheel. If you are, then the speedo head itself is the problem. IF the odometer part of the unit is working now, then that does mean the sender is fine. I didn't inquite when you told me the 'speedo' wasn't working, but in any case, the sender is good if the odoworks and you will need to remove the cluster. Let me know about the prndl setup and if you have a column shifter.
Roland
Roland
---------- FOLLOW-UP ----------
QUESTION: Hi Roland
I checked the sending unit as you said and I get no pulses. I've tried it in neutral and in gear. The car is an automatic with shifter on the floor. I checked the tach before I re-installed the cluster and it was working but now it has quit. So now neither the tach noe the speedo are working.
How do I find and check the sending unit for the tach and how do I remove the connectors on the back of the cluster. I pulled on them but they didn't seem to want to come out & I didn't want to pull too hard in case I broke something.
Appreciate any further assistance you can give.
Kirt
ANSWER: Hi Kirt,
I would suggest in the absence of pulses from the sender unit, if you are measuring at its immediate connector, that a new sender is likely needed. The tach is based upon pulsing from the crank sensor which is incorporated in the engine control computer. I would take out the dash before doing anything about the tach "sender", because there is none for that purpose only. If you have spark, you have a tach signal.
Roland
To remove the cluster: disconnect the battery
Remove the cluster bezel
remove rear window defogger bezel and radio bezels
remove upper steering column cover
remove 4 screws attaching cluster housing to the base panel
pull cluster rearward and disconnect the two plugs by reaching behind it
remove the cluster assembly.
The distance sensor pulses arrive directly from its connector at pin L of the red plug (white/orange wire)
The tachometer pulses arrive from engine coumputer on pin H of the gray plug (gray/light blue wire)
The tachometer does have a replaceable drive module on the edge of the unit.
---------- FOLLOW-UP ----------
QUESTION: Hi Roland
I bought a new sensor for the speedo and that worked. Now I'm going to try tracking down the tach issue. I guess the red and grey connectors at the back of the cluster just pull straight off. Is that right?
How do I know that the cluster is getting the tach pulses?
AnswerHi Kirt,
Yes, the plugs pull straight off.
On the tachometer:
It is probably a rapidly pulsing voltage signal which may not be easily detected with a simple DC vom meter. But you could see if you can detect any change in the voltage reading with a digital voltmeter between the wire and ground when you start the engine. As I mentioned there is a tachometer drive module that could be replaced if you find you do have signal. An AC digital voltmeter should read 1.0 volt with the engine running, but a DC voltmeter probably won't detect that at all. That wire is connected to pin 43 of the engine controller, if you want to verify that. If you do have the signal, and the 12V to the two plugs I mentioned in my follow-up, then replacing the tach drive module would be in order.
Roland
