Clio 172 Cup Hazards Lights Flashing Possible UCH Issue

[Flook]

Recently been having an issue where my hazard lights which are constantly flashing no matter what state the car is in and causing the battery to run flat. Only way to stop this is to pull the fuse for the hazards.

I have checked over the obvious,

- Disconnected the hazard switch
- Cleaned up the earths in the boot
- Cleaned up the earths behind the N/S/ headlamp
- Disconnected the alarm
- Pulled every bulb from the holder

Nothing to do with the rear light bulb holders or connectors, nor the number plate light.


I can only now think it's something todo with the UCH/BCM and if it is, it's the only fault being caused by it. I am yet to remove it, but the car has been dried stored for the last 4 years and is never driven out in the wet, externaly there doesn't look to be any signs of wet, nor is the drain holes blocked in the scuttle panel. Again I should remove the UCH to inspect for any damage tomorrow.

Some visual checks of whats happening,

1st:
Ign on
Hazard fuse removed
Hazard switch removed
Left indicator on dash flashes
No sound

2nd:
Ign on
Hazard fuse back in
Hazard switch connected
Hazard symbol flashing on dash
Sound
Hazard light switch flashes very slowly and faint

3rd:
Same as 2nd, but with the hazard switch removed

* Red LED by the gearstick does random flashes, no issue with starting the car.


Would anyone have any input or experience with similar issues? Or anywhere else I can test that I've not mentioned. I am thinking of going to the scrappy and plugging in another UCH to see if the hazards act normal. If they do, I'll then work out what how to go about repairing mine.

 

[Adey]

I'd check the half sized relays by the uch. They tend to corrode internally, sit right above wet feet and such. You can open them up to see. That said it could also be a uch fault doing simillar. Take a look inside and check for corrosion

 

[DaveL485]

Start unplugging stuff until it stops, follow the clues.

And check all your earthing points.

 

[Flook]

Start unplugging stuff until it stops, follow the clues.

And check all your earthing points.

I a

 

[Flook]

Someone from work had a spare UCH, plugged in and everything works as it should. Found a complete ECU on eBay, i've ordered this to get me back up and running and in the meantime I will send my faulty UCH to be repaired.

I can then have a backup for future.

Opened up the faulty UCH, no obvious sign of damage. Believe it could be one of the small resistors that sit under the multiplug.

 

[Adey]

must be an age thing, pretty easy fix though

you can virginise the ECU to pair it with a UCH or even remove the security chip off the old (current) uch and fit it to the spare uch yourself if you are handy with a soldering iron

 

[Flook]

Yeah I guess so,

So I do have a heat station and I might try removing the EEPROM so I can put this into a working UCH. Least this means I will always have a spare working ECU, UCH and Key. Dan is going to pull the code off for me so I can get a 2nd key.

Will let you know how it goes when I get around to it.

 

[Brigsy]

Send uch off to dieselpumpspecialist for repair.