Hello all,
I bought a 1996 XJS Celebration convertible 6 cylinder 4,0L (243) automatic .... a beautiful car!
The guy told me the speedometer and cruise control stop working. The needle stays at zero.

I am not a mechanic .... chemist by trade .... and I can cookbook!

If someone can help me out abet?
what should I try first and please keep it simple as I don't know too much about working on cars. (I'll need to know the location of the parts to test.

Thanks for your time and efforts,

Tom F

 

Tom: I am not that familiar with speedometers, but their are details on this site if you do a search. I don't think you have a bad speedo. I would suspect the sender. It is located in the transmission, I believe!
You should buy a shop manual for your car if you are going to work on it yourself. Once you fix the speedo your cruise should work

 

The speed sensor is on the rear differential cover. It's a magentic pickup that senses a toothed wheel inside the differential. From there, it goes to a speedometer interface unit in the trunk, behind the left gas strut support and gives a speed signal to the cruise and speedometer.

Power is fed by Fuse #16 (5A) in the left fuse panel, which is behind the under steering column trim. I can't remember if that panel has to come off, I think so. It's a 1/4 turn fastener at the bottom and some screws.

I'd start by checking the fuse for power and go from there. Pull the fuse out and make sure it isn't blown.

If you want the electrical manual for the car, it's here: http://www.jagrepair.com/images/Auto.../jvs1995en.pdf

 

I am having a hard time tracking down this Sensor DBC11116. Here is my thinking there are GPS conversion kit to go from GPS to the speedometer. Would love too hear your guys thoughts on this? I just can't keep driving the car racking up miles and odometer show the same miles the day I bought it ..... its dishonest.
so if anyone has converted please leave a link.

Thanks again for your time and efforts into this matter

 

I doubt the sensor has gone bad, there are no moving parts in it. It's possible the interface unit has failed, but I'd check the wiring for breaks or abrasions too.

The sensor has to be a specific distance from the pickup teeth, I believe no more than 0.050" There are shims under it to adjust the spacing. It should have been set up at the factory and not move after that. Unless the bolt has backed off and the sensor has moved?

 

Thanks that gives me hope! I will check it out this up coming weekend. I bought the car last weekend and he said he test it with a meter (ohms) I am guessing and I believe he said it had a zero reading??? (would that be a bad sensor or a broken wire) The interface unit would that be in the trunk or in the wheel well?
So I'll check the following:
1. Check Fuse (I'll replace it good or bad)
2. Start from the sensor look to see if it good and tight
3. Follow that to the interface looking for damage to the wires "breaks or abrasions ".
4. Anyway to test interface?
5 Follow wiring to speedometer and checking for good grounding.
6 If no problems found replace interface unit.

Thanks again you guys rock!

 

With the rear wheels off the ground, if you attach a meter to the leads from the sensor ( which might be in the front of the trunk, I can't exactly remember where mine was) and spin the wheels you should get an AC voltage. Not much, as the voltage is speed dependant, but you should get something. At hand rotation speeds I think you'll get something in the region of 2 volts. As long as it's non-zero the sensor is working.

I don't know how to test the interface unit, but what is starting to affect electronics at this age is dry and cracked solder joints. If you're handy with electronics it's possible to touch a soldering iron to the joints on the board in the interface unit and reflow all the solder connections. I've brought a number of electronics back to life by doing that.

 

Same for me... I tried cleaning the instruments circuitboard and I cleaned the connection from the speedo transducer to where ever it goes? After doing that... started the car and the speedo is showing 50-60mph at idle. Haha I think I made it worse