I have a 1990 740 Turbo and the speedometer/odometer doesnt work. I bought the car this way and now i want to fix it. Also the antilock brake light is on, I remember i read somewhere that when the anitlock brake light comes on the speedo will not work? Also the mechanic checked the speed sensor and he said it was fine, I even put in 2 different clusters and it didnt fix it.

 

Check the wiring from the Rear speed sensor.

If that is ok then you will need to back track from there.

 

yes i forgot about asking about that. now next time i get an oil change i will look for that, I am getting one soon. now is the wires in the pumpkin? or someplace else? also how do I remove my windshield wiper fluid bottle, it doesnt work and I need to put in a replacement

 

Yes the wires in the Pumpkin.
I forget exactly about how to remove the bottle. There should be a screw or 2 holding it in.
I haven't taken one out in about 3 years.

 

well thats good, i could always have the mechanic change the rear oil in the pumpkin and he can look at the wires. can he check them with a meter to see if its good or not?

 

There is a way but I don't have the specs here.

 

you could check the wires from the pumpkin one should show a pulse if you use a logic probe. The speedo gets powered straight from the ign switch on my car this is a black wire with a red stripe. This wire with the two from the pumpkin plug into the back of the speedo. If this power wire is not plugged up the car will not start because it supplies voltage to all the other lights on the dash and power to the coil. So you know you already have this so the two wires to the pumpking or the pickup on the rear end is probably at fault. Sensor is quite expensive I think I saw it somewhere for $120 the two wires come into the trunk along with the wires for the in tank pre pump. hope this helps

 

Curious, I just recently made a post about my odometer. I have a 90 740 GL Rex. Did you ever get your speedo fixed.

My problem is not the speedo, but odometer. My speedometer works fine. You can read the post just a couple of days ago.

How did you fix it, if so?

Thanks,
Kevin

 

youre all screwed. they can't be fixed, already tried, already cried

 

Please explain??