Technical Earth Issues

[DaveMcT]

Regards odd wiring problems. IIRC, Punto Mk2(a) automatics would throw a gearbox wobbly if the reversing light was faulty. Anything from switch to bulbs or earth could upset it.

 

[DiamondDave]

Thank you guys for this helpful discussion.
Just preparing a 2011 69 bhp Dynamic for my son to learn to drive in. Well, it's my car now instead of the Alfa 159 I had up to last week. The car also has strange light issues. 1) Parkers on - fine. 2) Dipped headlights on - front ns parker goes off, ns indicator lights dimly as does rear ns indicator.
Checked ns rear light cluster connector and the centre wire shows signs of heating and discolouration.
I gave it a bit of a clean and adjusted the contacts but still have this issue.
I'm going to replace this connector anyway, but is it likely this is the only issue do you think?

Thanks, Dave

 

[koalar]

The rear all sounds like the earth centre commector to me

Get that sorted first

rear light cluster repair | FIAT Panda (Mk3)

pretty self explanatory this one was flashing double speed when using the brake 10mm socket is so much easier press here to release the connector above done forget to clean up the other half. Scrap with a screwdriver blade is normally enough above, Line up these First.

www.fiatforum.com

You can pop the terminal out

You yave to clean the bit the plugs fits into as well

An auto electrician would just cut it off and replace they are about £0.10 each

 

[DiamondDave]

Before I put this back together, any suggestions as to where there could be other earth points?
This is what I found.
1) On nearside wheel arch behind back door.
2) Nearside passenger footwear on wheel arch
3) Under battery on front main beam beside main battery ground leading to gearbox
4) Behind battery, above ABS pump on suspension tower.
5) Under plastic panel, on metal cross panel, beneath wipers.
6) Earth point behind Airbag module on centre tunnel under heater unit.
7) Top left corner of pedal box on bulkhead

Any more to check?

I have replaced both rear light cluster wiring connectors and cleaned all these earth contacts, but still have my lights issue.

 

[koalar]

Before I put this back together, any suggestions as to where there could be other earth points?
This is what I found.
1) On nearside wheel arch behind back door.
2) Nearside passenger footwear on wheel arch
3) Under battery on front main beam beside main battery ground leading to gearbox
4) Behind battery, above ABS pump on suspension tower.
5) Under plastic panel, on metal cross panel, beneath wipers.

Any more to check?

I have replaced both rear light cluster wiring connectors and cleaned all these earth contacts, but still have my lights issue.

What year
What engine
What problems


if you put the indicators on and press the brake

do the indicators change speed

do the brake lights change brightness in time with the indicators

have you checked the body computer connectors for melting

 

[DiamondDave]

2011, 69BHP VVT.
Parking lights come on fine.
Indicators work fine.
When headlight dims or main beams are turned on, left front Parking bulb goes out and left front and rear indicator bulbs light at half capacity.
Brake lights don't change.
Have checked body computer and not a sign of burning. All fuses ok.

 

[koalar]

Perfect

When there is a higher load, there is a voltage drop due to high resistance somewhere

We need to work out if it's on the ground side or the power feed side problem first

Do you have a multi meter or volt meter

 

[DiamondDave]

Ya. Been measuring voltages at the bulb contacts between left (near) and right (off). Offside, seems normal, 0V at ground, 12V for dim and 12V for Heads.
Nearside is different, voltages not as expected. Bit weird to be honest.
Dims and heads came on together, more on nearside than offside.
Stripped out the body computer to check for burning etc. Nothing there, not a sign of damage.
It was suggested, as its probably a grounding issue, to ground the nearside to bypass the fault. No success, just blew a fuse.
At a bir of a loss, to be honest.

 

[vidtek]

Old thread I know, but very strange things happen with most cars after fender bender type accidents. Spray shops do not always ensure there is a good earth connection between replaced/resprayed body panels, and this is where many of these issues arise. Many cars on the road with a dim headlight for instance are usually caused by this, as is crackly radio reception after a repair. An easy diagnosis is to use a crocodile clip lead between panels and see if there is a change.

 

[koalar]

Ya. Been measuring voltages at the bulb contacts between left (near) and right (off). Offside, seems normal, 0V at ground, 12V for dim and 12V for Heads.
Nearside is different, voltages not as expected. Bit weird to be honest.
Dims and heads came on together, more on nearside than offside.
Stripped out the body computer to check for burning etc. Nothing there, not a sign of damage.
It was suggested, as its probably a grounding issue, to ground the nearside to bypass the fault. No success, just blew a fuse.
At a bir of a loss, to be honest.

Right it's does not appear to be obvious or common fault

The bulb that goes out when you turn the main lights on

Remove it

Test as before do the indicators still dim