Technical Intermittent Indicator/All Lights Issue - Can you help?

[RedPeril]

I'm having a problem with intermittent lighting problems,. The N/S rear indicator and entire lighting system occasionally fail to work.


The N/S rear indicator occasionally flashes at double speed.

The N/S tail light occasionally flashes with the indicator.

The entire lighting system occasionally fails for a second or two.


From what I read, the fault is something to do with an earth fault? How can I track down what to fix? Where do I test, and presumably with a multi-meter?

It's a 2009 1.4 Grande Sport.

Any ideas or suggestions would be great.

 

[CarMan1230]

Sounds like you have broken wires somewhere, I'd check all wiring looms from where the boot and doors close, had to replace wiring loom in boot of my one and repair wires in the doors from where it opens. U might beable to just wiggle the wires to see if lights flash etc.

 

[oldmanhouse]

Problems with the rear light clusters seems to be a common problem with the GP. CarMan1230's suggestion of checking the wiring to the rear light clusters is sound advice. It's come up on the forums plenty of times that those wires had deteriorated, or the connections on the plug had corroded (clean them up with fine sandpaper / wire brush). Example: https://www.fiatforum.com/grande-punto/482954-wireing-gremlins.html?482954=#post4556682

More general stuff you can check is the earth points in the engine bay and fuse box, especially if your front lights are intermittently failing too. Another common GP issue.. Guides here:
https://www.fiatforum.com/grande-punto/318839-electrical-gremlin-thread.html
https://www.fiatforum.com/grande-punto-guides/169204-grande-punto-engine-bay-earthing-points.html

I'm not sure where the earth point for the rear lights is, as that might be worth checking too. Somewhere under the boot carpet I imagine, perhaps someone else knows?

 

[RedPeril]

Thanks for the reply and links. I am still working on it! I'm going to brighten up the contacts that can be seen once the light cluster is pulled off. After this, it's a voyage into the unknown.

Would I be correct in saying that if there is a fault on the earth that runs from the battery then it would affect both left and right-hand lighting? This fault only affects the left-hand side.

Any further thoughts would be received, gratefully.

 

[RedPeril]

I've checked the bulb fittings for rust for both the NS/R indicator and taillights and the NS/F indicator and sidelight and all are free of corrosion. Following the links the earth points that are identified are all sound. I couldn't understand the "green to green" and "purple to purple" test so can anyone help me here?

All of the small connectors that engage between the plastic light cluster and the plastic seating on the rear of the car have been brightened up and look good.

I guess just replacing the light cluster isn't a very smart strategy without tracking down the fault?

Any ideas would be received, gratefully!

 

[markfor]

Wiring loom from boot lid Brown wire broken What does Brown wire do?

 

[varesecrazy]

@markfor
Only 3 (or 4)things on that circuit

Boot release?

Brake light,wiper motor,heater element

That the 1 thing in 150,000 miles of ownership Ive never had to look at

What doesnt work?

 

[markfor]

Everything seems to work except high level brake light Also what looks like water hose for rear W wiper cut. 2006 G punto