2007 Merc GL350

Exterior Lights Faulty – not working properly

Exterior lights faulty – Into our workshop was this lovely Mercedes GL350. The customer complaint was with the exterior lights, some not working and some on all the time so flattening the battery.

A quick serial scan showed various communication errors from the rear SAM. Access was gained and straight away the fault could be seen

Water had gotten into the module and damaged it. The module was removed and stripped to see if a repair was possible. The condition of the pcb was beyond repair.

A new genuine unit was sourced and fitted. Adaptions performed, all external lights and all other functions controlled by the SAM were checked for operation and with everything OK the customer picked up the car,  happy with a first time fix with no unwanted parts and no guess work.

XSARA PICASSO Airbag fault

Airbag Fault Issue

Airbag fault – This vehicle came in with a intermittent airbag fault. Fault codes related to left hand side crash sensor.

To gain access to sensor passenger seat was removed and the carpet lifted.

Wiring was checked for resistance between sensor and airbag module and was all good.

All power and grounds were load tested at the module and found to be good..

The module was tested faulty. A substitute module was sourced and coded to car.

Another car diagnosed correct first time. No wasted expense on unwanted parts.


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Peugeot 207 roof trouble

The roof on this vehicle was inoperative.

A fault code for left boot lock switch open/short circuit

The switch is located within this roof hinge. We tested switch OK. So the loom was removed and examined and a break found. We reset roof, cleared fault codes and the roof was fully operational again.

Citroën new keys


Citroën C3 in for a central locking problem. Car would start but customer couldn’t lock the vehicle with either of their 2 keys.

A quick check of the keys revealed that neither were emitting a signal.


A new key from stock was coded in using specialist equipment, at less than half the price of the dealer.

Mercedes E-class


Into our workshop was this Mercedes which had a fault where intermittently the key wouldn’t turn in the ignition switch, this is a infrared key. Through a series of tests it was found that both keys were faulty and also the EIS(electronic ignition switch).

A new key was priced at £240+vat and the EIS at £425+vat. With the age of the vehicle was not something that was viable. Another option is to change various components on the car relating to security because everything is coded and needs to match, so a 2nd hand EIS unit would not match the engine ECU and also the ESL(electronic steering lock).

We managed to source a complete set of components


These were all fitted, the steering lock is particularly hard to fit as it was in the locked position so is hard to remove.


With the new kit being off an estate car we had to perform adaptions on it so the electronic boot release would work.

Another happy customer saved from perhaps having to scrap the vehicle.


Audi Airbag Light on


This Audi was in our workshop with airbag light on. A quick scan with our autologic showed internal fault in airbag module. We stripped the dashboard down to gain access to the module to check connections at the unit.



Quite a few items have to be removed to access the module.

The wiring was confirmed OK. So using our VAG Airbag tool we are able to reset the hard data within the module saving the customer the expense of a new unit which in this case was over £400.


BMW 3 Series battery drain


This came in with a battery drain amongst other troubles.

The drain wasn’t on any fused circuit, at this point many workshops may have struggled to isolate the fault. Here at Widnes Auto Electrical we have specialist tools and training for such faults and using our thermal imaging camera we could scan the vehicle for any hotspots where current is being drawn and heat generated.


This picture shows the electric ariel after the vehicle being stood overnight still showing 48.8degrees. The camera can see this even when panelling and carpet insulation in in the way.

Radio coding


Mercedes radio in for coding

E90 BMW airbag fault


The airbag light was illuminated, a quick serial scan showed passenger occupancy sensor fault a common issue on these cars. A quick test of the wiring confirmed all OK up to seat.

A lot of people then fit a module that kids the car into thinking someone is sat in the seat and so turns the light off, a cheap but dangerous repair. The purpose of this sensor is not just to see if the seat is occupied but also the weight of the person so if a small child was sat in the seat in the avent of a crash through airbag would not deploy as it can do more harm than good. With this module you lose that function.

Luckily this customer understood the dangers and went with a correct fix. The customer sourced there own sensor which we tested first as fitting is quite fiddly as it sits in the seat underneath the cushioning


With the seat refitted and all codes cleared car was fixed