adamfogerty

Hi,

The speedo on my 1990 C4 sometimes fails to work...but if I gently give the glass of the gauge a few "taps" with my knuckle (much like you might knock on a door) then it springs back into life and will continue to work until the end of the journey.

Passengers think it's most amusing that I have to resort to quirky things like this to get my old car to work :-)

Anyone heard of this before or know what might be at fault?

Sometimes it works fine right from the get-go and doesn't require any manual intervention...so it's an intermittent problem. There are also no warning lights associated with it.

Before I pull the gauge out to look at the connections on the back I'd like a vague idea of what I should be looking out for.

Thanks,

Adam

Uber 911

Adam, I had a similar problem with the OBC tacho on my 964. Took it out checked all the joints on the rear with a small wire brush and a sqeeze of WD40, slotted it back in - Problem solved

AOW162435

My '95 993 (6/94 build) does this in the winter. A quick rap with my knuckle solves it.


Andreas

vidarnz

I get this with my Jaguar. I dont want to fix it as I think it gives my car personality.

Like you, my passengers find it amusing.

Computamedic

Adam,

I'm not 100% convinced by this - but I had a similar problem some time ago where the speedo refused to work (and the rear spoiler woiuldn't come up because of it) and I had other symptoms of the classic "bad solder joints in the clock" issues. Once I'd resoldered the clock joints the speedo problem never occurred again.

I wonder if your rapping of the speedo just causes enough vibration in the clock to overcome the problem?? It's just a thought.

Regards

Dave

lunchboxbill

mine has does a couple of times, both just after giving her a wash.

vasculardoc

I've just developed the same problem and was about to do a search on the list to find a fix.....speedo coming and going for no apparent reason....quick rap and it gets better.....and...I put the car through a car wash 3 days ago just before it started.....is it worthwhile just watching and waiting (ie does it get better on its own if it is associated with a recent wash), or should I take it out and resolder all the bits on the back etc. As an aside....its varying between 32 and 41 degrees C in adelaide at the moment, so if it is a moisture problem in the car, it'll dry out pretty quick !

Mark

lunchboxbill

Could this also be the reason as to why my brake pad warning light is on - even though they were replaced about 500 miles ago?

apologies for the hi-jack

jimq

unplug and replug in the connectors on the wheels. It could be a bad contact or if the sensor came loose from thepad it may have worn thru and caused the light.