I think I have wired up my VDO speedo incorrectly. So I need to know what is a Reed switch?

Is it a Oscillator sensor
or a Inductive Sensor
or a Hall-effect Sensor
or a hall-effect sensor with an open collector circuit

It looked like an Inductive sensor on the diagram that i got from low-tension but it will not work.

Thanks Carl

The blue wire goes on the number 8 terminal. Take the other 2 for power to the sensor from the same as into the gauge, 3 and 4 I think they are.

[Edited on 26/3/05 by Peteff]

I only have two blue wires fitted the sender and I attached them to 7 & 8 with live going to 4 and earth 3

Graham, Pat say's you know what sender I have it the same as his. The little threaded thing about M6 x 25 with 2 blue wires coming out of the top.

Thanks Carl

make sure it doesnt need a positive pull up. my telemetrix one did, and puzzled me for ages.

hth
tom

Isn't there a thin red and a green to the sensor as well for power in and earth?. There was on the one we had but it was a flat plate and has an extended range 300% greater than previous ones. Check if it has terminals to fit the wires to. 4 and 3 are power for the gauge not the sensor.

Try this link - I think it covers the reed switch sender you are describing
Caerbnt Instruments (smiths telemetrix)

I purchased a vdo sender which was the inductive type. I fitted it yesterday, this has 2 wires running to it from pins 7 and 8 on the speedo - signal to speedo and feed to sender.

Mine was initially picking up interference through the loom from the coil and was acting almost like a tacho, and its a westfield loom made for these instruments. I had to run 2 separate wires from the speedo down to the sensor - bloody amateurs !!

With your sensor be careful to set it with the car on the ground, I had one originally and snapped it once the car was on its wheels and rolling.

Peter.

We had a problem with the speedo sender hitting the propshaft 10pm the night before the SVA test didn't we Pat.
Thanks to Graham who saved the day.

Carl

Sorted it!!!! It was wired correctly but the switch was faulty. Had it up to 40mph on the axle stands tonight.

Thank Carl

Did you get it from dodgy Pat? Speedo senders are not his strong point!

Hmmmmmm what can I say