Citroen Relay 2.2 2003 - Boxer/ Relay van speedo gone crazy!

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Sun 10 Apr 2016 14:51
Citroen Relay 2.2 2003 - Boxer/ Relay van speedo gone crazy! - Citroen Surf Bus

The speedo was dead when I bought the van, so I bought a new sensor.(which is mounted on the gearbox, there is no cable)

Now the needle waves wildly between 0 and 100mph! (And the odometer continues clocking up the miles - fast!)

Weirder still - it does this even when the vehicle is stationary.

Bought a good second hand instrument cluster - but the problem is unchanged.

Anyone out there seen this before? Or is my van haunted?

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Sun 10 Apr 2016 19:30
Citroen Relay 2.2 2003 - Boxer/ Relay van speedo gone crazy! - elekie&a/c doctor
I assume this is a 3 wire sensor.you need to check the integrity of the wiring.One wire will be an ignition,another will be the signal wire back to the speedo head,and the other must be a good earth to chassis.Does the fault still occur with the sensor disconnected?
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Wed 13 Apr 2016 18:50
Citroen Relay 2.2 2003 - Boxer/ Relay van speedo gone crazy! - Citroen Surf Bus

APOLOGIES!

I was expecting notification of replies - but it seems there is no facility here - sorry for late reply, very grateful as I'm out of ideas!

Any advice on finding the appropriate chassis earth without a workshop manual?

I found a reference to changing the 'interface' box under the dash - any idea what this is, and what it might have to do with the speedo?

Will try disconnecting sensor as suggested, thanks.

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Wed 13 Apr 2016 20:03
Citroen Relay 2.2 2003 - Boxer/ Relay van speedo gone crazy! - elekie&a/c doctor

If you have a bad earth to the sensor,then just run another wire from the earth wire at the sensor to a nearby fixing that is bolted to the chassis.Early Peugeot 406 models from the mid 90s had a speedo interface box behind the glovebox,but I not too sure this van has it fitted.

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Wed 13 Apr 2016 21:41
Citroen Relay 2.2 2003 - Boxer/ Relay van speedo gone crazy! - Citroen Surf Bus

Priceless! Thankyou for that.

I'm guessing your hunch is that this IS a bad earth symptom?

I'll let you know the outcome. ( :

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Wed 20 Apr 2016 20:17
Citroen Relay 2.2 2003 - Boxer/ Relay van speedo gone crazy! - Citroen Surf Bus

Dammit!

I don't have a wiring diagram, and can't figure out which is the earth wire.

I was hoping one would be black - but that would be too easy, right? ( :

With my voltmeter, at the connector (pulled off) and ign on -

one reads 7.5v (grey/black),

another (mauve/black) 1.25v

and the other (mauve yellow) read zero, or a trace of 0.3v.

That's me stumped!

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Fri 22 Apr 2016 19:09
Citroen Relay 2.2 2003 - Boxer/ Relay van speedo gone crazy! - Citroen Surf Bus

The fact that Citroen/ Peugeot wiring diagrams are locked in a silo under the Pentagon doesn't help one bit!

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Sun 25 Sep 2022 23:17
Citroen Relay 2.2 2003 - Boxer/ Relay van speedo gone crazy! - firemoth

Blast from the past..... I know it's been 6 years but this is the first I've seen of someone else with this problem! I don't have the speed issue (yet?) But my mileage clocks up when when not moving, approx a mile every 4 seconds. Did you ever narrow down the cause? Cheers

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