black cable cut behind dashboard

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bekes
480 Newbie
Posts: 5
Joined: Fri Jul 26, 2019 7:05 pm

black cable cut behind dashboard

Post by bekes » Mon Mar 09, 2020 10:00 pm

Good evening, I'm lucky I had my dashboard reconditioned by robert. I just passed the technical control after 13 years of immobilization. :)

Unfortunately I don't have any speed indication even after removing the airbox connector.
Maybe I am lucky:
Between the two green and grey connectors there is a black cable that is cut.
My question: I can not identify the arrival of this cable.
Should I connect it to the little blue connector that encloses a white and red cable.

Thank you for your answer.


jean-henry douzon

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brinkie
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Posts: 857
Joined: Mon Apr 21, 2014 11:20 am
Location: The Netherlands
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Re: black cable cut behind dashboard

Post by brinkie » Tue Mar 10, 2020 12:38 pm

Hello Jean-Henry,

First of all: measure the resistance over pin 6 and pin 12 of the grey connector on the cable side (not on the instrument cluster itself). It should be around 3 ohm (can be a little more, but not more than 10 ohms)

If you measure open circuit (infinity), measure across the cable under the air box. If you measure open circuit there, the sensor is broken. (I have a replacement)

If you measure approximately 3 ohms across the wiring to the sensor, you can try and replace the wiring between the connector under the air box and the instrument cluster (this was the fault with my car)

Run a cable from the connector under the airbox (i.e. directly wired to the sensor) to the instrument cluster. The wire to the sensor has two colours: yellow = signal and brown = return.
Pin 6 of grey connector goes to yellow cable = signal
Pin 12 of grey connector goes to brown cable = return

But... if you measure correct resistance across pins 6 and 12 of the grey connector, there may be a loose connection inside the connector! What I did was applying a tiny bit of solder to pins 6 and 12 on the instrument cluster, so the connection became very tight.
Robert.

Present cars: 1994 Volvo 480 GT 2.0i, 1999 Volvo S70 2.5 Europa, 2010 Volvo V70 2.0F Momentum

Alan 480
480 Is my middle name
Posts: 1489
Joined: Sun Aug 28, 2011 9:03 am
Location: Aberdeen

Re: black cable cut behind dashboard

Post by Alan 480 » Tue Mar 10, 2020 12:41 pm

bekes wrote:
Mon Mar 09, 2020 10:00 pm
Good evening, I'm lucky I had my dashboard reconditioned by robert. I just passed the technical control after 13 years of immobilization. :)

Unfortunately I don't have any speed indication even after removing the airbox connector.
Maybe I am lucky:
Between the two green and grey connectors there is a black cable that is cut.
My question: I can not identify the arrival of this cable.
Should I connect it to the little blue connector that encloses a white and red cable.

Thank you for your answer.


jean-henry douzon
well done on getting another car mobile :hopping:

the cable for the gearbox pick-up is buried within the main harness on the GREEN plug , it IS a small black cable approximately 2mm diameter .

not sure about the small blue one, there is a two pin for the air bag monitoring, but on mine I'm sure it is WHITE

OK , see Brinkie's more complete response . . .. . . :wink:
Alan

480 ES 2litre 'Celebration' ? , C30 1.8ES, SS1

bekes
480 Newbie
Posts: 5
Joined: Fri Jul 26, 2019 7:05 pm

Re: black cable cut behind dashboard

Post by bekes » Wed Mar 11, 2020 9:16 pm

Thank you robert for this procedure

I took the strength measurements of pin 6 and pin 12 separately.
I started the circuit from the + of the battery.
I get for pin 6 a measurement of 22 ohms and 1 for the return pin 12

However I am hopeful because the speedo needle makes some movements up to the 20 km/h indication when I drive.
Tomorrow evening I will try to take the correct measurements. I still have some work to do before I get a job at Philips :D

bekes
480 Newbie
Posts: 5
Joined: Fri Jul 26, 2019 7:05 pm

Re: black cable cut behind dashboard

Post by bekes » Wed Mar 11, 2020 9:30 pm

Hello, Alan,
this black cable is powered by 12 volts.
I don't see what it's for.
Maybe to the indicator repeater on the left fender of my car which has no more cable.
There is only one possible connection on this disconnected cable.
thank you for your interest :)

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