New to Forum Rear Lights not Working Blowing Fuse Solution/Fix

September 23, 2022

As a new member, rather than simply joining to ask for info, I thought I'd share this puzzling Aygo problem I came across last year.

The car is an Aygo Mk1. It belongs to a daughter of one of our neighbours. She'd visited a few garages and they couldn't find out why the fuse for her tail-lights was repeatedly blowing. One charged her £135 for the privilege of not fixing it, suggested it needed a new wiring loom, which would cost a quoted, with labour around £1250 to £1400. I don't know what they'd do when they found out it was still blowing fuses?

Furthermore, as a new loom is over £1k plus VAT, I wonder just how new the new loom would be...

Solution: the fuse you are interested in is fuse# F21 on Left side of the instrument panel, but double-check in the owner manual. Please note too that OBD-2 did not throw up any codes and also that English is not my first language.

The Cause: is usually down to one of the headlight levelling motors that's seized, is sticking or has water ingress. The resultant is an Excessive Current Draw, which obviously blows the mini-fuse. The get-you-home fix (you won't have any tail-lights or even number-plate light showing) is to disconnect both levelling motors. It is fairly easy to see which one of the connectors to pull. And of course replace the fuse.

Fit a new branded-quality fuse (as cheap fuses are a false economy) and replace both motors (they both do the same amount of duty and the other motor is sure to follow suit) when you get home. It may only cost a little extra to get two complete headlight units complete with the servos already fitted. Plus! the new headlamp units would be free of ugly plastic lens haze. For a while, at least seven months?

NB I suggest swapping both motors as both tail lights-stop working AND the number-plate illumination lamp also goes out when the mentioned fuse blows and, bearing in mind the possibility of a rear end shunt at night, it is surely sensible to replace both.

More correctly called servos, headlight motors are under £20 new on eBay, or £68 inc. discount from Euro Car Parts if you're stuck.

Thank you for letting me join TOC. Regards, Donald.

Finally...

Mostly from personal experience and partly from checking cross-reference in catalogues (the TRW Company are to be credited as their online catalogue shows that with Every Single Part that they make, they list Every Single vehicle that the Specific part will fit, regardless of year or marque. Moprod are also useful, but not so upfront as TRW), I am beginning to compile a parts compatability list of what parts from Mk2s will fit Mk1s.

As many Mk1s are higher mileage cars and all are at least eight years old, used parts from them are often worn out. I've already researched the braking, steering and suspension systems. So what parts are basically the same?

The answer is, regardless of part numbers suggesting differently, a lot. A very lot. Particularly with the often swapped parts that are fitted owing to the usual wear & tear.

So health permitting (I am writing this in hospital, five hrs after a general anaesthetic) I will post a list of what parts I have ever swapped myself, or am certain about exact compatability. Some Mk2 parts have benefitted from a revision of design or materials.

There are still many very low mileage late model vehicles being broken on eBay. I fitted a Mk2 engine to my neighbour's C1. At 900mls & £180 delivered on a pallet, it is a cracking engine, professionally removed. A nearly new radiator pack was a £18 delivered as the seller couldn't remember if it was for an Aygo or Yaris. I think an older Aygo can be made into close to an as new car using low mileage parts. I consider the Aygo et al is a masterpiece in an engineering solution to making a modern motor car that is fun to drive (as close to a go-kart like driving experience as one can get for the cost) plus that amazing fuel economy from such relatively low tech.