Hi,

Immediately after passing the 200,000 mile mark :worship:, my Croma 1.9 8v seems to have suffered a bit of a mid-life electrical crisis.

Whilst the roof level brake light works perfectly, the low level brake lights have stopped working. The bulbs have been checked and replaced and are fine, and the tail light part works, but the brake filaments do not light up.

At the same time, I have noticed that three of the dashboard warning lights remain very dimly lit at all times (it's hard to see them in daylight, but they are obvious at night).

I assume that it is probably an earthing problem, although googling suggests it may also be a fault in the body computer or the instrument binnacle.

Could anyone please help? I have no idea where to find the earths or how I would go about replacing the computer or binnacle. Are these likely to be expensive from a breaker?

Thanks

biguglycar said:

Hi,

Immediately after passing the 200,000 mile mark :worship:, my Croma 1.9 8v seems to have suffered a bit of a mid-life electrical crisis.

Click to expand...

Hi,
The high level brake light is connected directly to the the switch on the brake pedal whle the main lights are driven by the body computer. Does the brake light failure warning come on on the dash? If not, it's unlikely to be the lamp wiring or earths. Either the body computer is not seeing the signal from the pedal switch or the body computer is faulty or possibly the body computer input is faulty.. If you have a EOBD / OBDII interface e.g ELM327 and Multiecuscan or AlfaOBD (even the demo versions) you can tell if the BODY ECU is seeing the switch signal. We know the switch is OK because the same contact feeds the body computer and the high level light. The problem with a body computer fault is that it's part of the CODE system so has to be matched to the keys and other CODE units. One from the breakers won't work as is. There are some things that can be done to make one work but they need electronics skills.
The body computer is part of the fusebox behind the cover in front of your right knee. For a possible quick and easy fix, pull the plugs and refit them, ditto the fuses, especially F37, F49 & F51, if you are lucky it's just a bad contact. Another unconventional fix would be to use a relay to drive the low level lights with the coil connected to the higgh level. This could be done at the body computer location.
Where in the UK are you? If you are near Cambridge I may be able to help.

Robert G8RPI.

Thanks g8rpi,

The brake failure warning light doesn't light up.

I have tried pulling and refitting all of the plugs and the suggested fuses, but there is no change (expect that now the fuel gauge seems to have decided that the tank is completely empty!) (any suggestions on this?)

I did learn about the window safety check routine though - always good to learn.

Thanks for the offer of help, but I'm afraid I'm in Cheshire, so Cambridge is a bit of a trip away.

@biguglycar
Do you have access to Multiecuscan or similar?

Robert G8RPI

g8rpi said:

Stuff that I'm not allowed to quote because I have fewer than 5 posts

Click to expand...

I have a bluetooth OBDII device and TouchScan on an android to communicate with it, but really no idea what it's telling me, other than that it reports no fault codes

@biguglycar
I don't think Touch scan will let you see specific inputs easily, but AlfaOBD (even the demo vesion) will. Or it should, I just tried my bluetooth ELM 327 interface and it won't connect to the body computer. I'll investigate further and let you know.
With the full version of AlfaOBD or Multiecu scan you can also turn individual lights on.

Robert G8RPI.

@biguglycar
OK,
The problem with my connecting to the body computer was the well known ELM clone CAN termination issue. I modified the interface (removed 120 ohm resistor between pins 6 and 14 not easy on this little bluetooth unit) and can connect. With AlphaOBD it's near the bottom of the list "stop lights enabled". I only have the demo version so could not turn on the lights, diagnostics are inhibited in the demo version.
The fact that you now have a fuel gauge fault does point to a loose connection somewhere. An ODB interface with Fiat/Alfa specfic software is really the next place to go. Sorry you are so far away, otherwise I'd put my full version of Multiecuscan on it.
Robert.