We have a 2002 320D BMW. The left hand indicators flash fast but when we plug a trailer board into it they go to normal

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Customer: Hi we have a 2002 320D BMW. The left hand indicators flash fast but when we plug a trailer board into it they go to normal speed. We read the fault code as 4a trailer socket fault. Do you think it could be the trailer socket ecu and if so where is it?
Answered by philhbmw in 3 hours 14 years ago
Auto Mechanic

32 satisfied customers

Specialities include: Automotive Mechanic, Small Engine Repairs, Auto Body Repairs, Diesel Engine Repairs

Hi there,

The indicators flash fast when there is a break in the curcuit for example when a bulb blows.

When you connect the light board you must be reconnecting the curcuit.

You need to check the wiring and go from there.

Is this a aftermarket towbar kit? or factory fit? Need to know to answer question about where the ECU is.


Reply to philhbmw's Post: Hi thankyou for your reply, this is a factory fit tow bar with the swan neck that stows away. I think it may be in the ECU for towing as there is a fault on the reverse sensors as well.

Hi there

Iam guess that that you have check your lights on the car.

Also check the muti plugs that go th your light clsters this model had an issue with pins melting.

Failing all that and because this is a BMW system get your fault memory read out.

If i have help you please click accecpt.

Cheers Phil..

Did you have any info as to where the ECU is? Because as soon as you plug in the trailer board the indicators go back to normal.
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