speedo sender Xantia

pete woods · Post by **pete woods** » 21 Jun 2003, 22:51

The speedo on my 96 1.9 td has stopped working. I read a while ago that itwas possible to test the sender to see if if was faulty. Have searched but cant find it. Any one know how to do it?

ghostrider · Post by **ghostrider** » 22 Jun 2003, 04:07

Pete, from the haynes manual it sounds as if the transducer is on the gearbox and is accessed from under the car , must be near the final drive to make any sense. As for testing it I would think it is similar to the Tacho sensor and should therefore have a resistance reading between the two terminals on the tacho its around 75 ohms, if its like the tacho sensor the third wire will be a screen.
Peter
________
Drug Test Kit

pete woods · Post by **pete woods** » 22 Jun 2003, 22:58

Cheers for that. I'm sure that I have seen a definitive test for the sender on this forum in the past. thats what i'm after but it's not turning up on any of my searches.

David Goddard · Post by **David Goddard** » 22 Jun 2003, 23:31

One test, if you have found the sensor is to connect a meter across the two terminals. As Peter says, first check the resistance. If there is "something" there (other than a desd short or open circuit) it may be worth checking that it is generating a signal.
Run a pair of wires into the car and look for an increasing voltage as the speed increases. Set the meter to AC Volts. I would expect to see several volts generated at 30 mph.
As sensors are simply magetic pick ups, I would suspect the actual speedo. Check that it has 12V supply and that the earth is OK.

pete woods · Post by **pete woods** » 23 Jun 2003, 00:23

Thanks, I'll have a go next weekend

wheeler · Post by **wheeler** » 23 Jun 2003, 01:45

as this is a hall efect sensor it needs a power supply & earth,unlike the tacho sensor (inductive type) which produces its own voltage.heres my method of testing them which got a result.i should have mentioned that the sensor has to be plugged back into the loom when testing. http://www.andyspares.com/discussionfor ... ignal,wire