Hi there,

I need to change the GEM (passenger compartment fuse box) coz it's got the rear wiper relay integrated within it. What numbers and/or letters have to match on the 2 units when buying a second hand unit from a breaker?

Thanks

As a minimum I'd say looking at the part number you'd need to match the prefix (first 4 numbers/letters like 3M51 etc) then the base number (format 12A123 ish) and the first letter of the 2 letter suffix (AA etc). The second letter of this is just the engineering level of the part but if the first letter is different this indicates a different variant.

Course it could be that other level GEMs will work in your car but best getting someone to confirm that before spending your money

As a minimum I'd say looking at the part number you'd need to match the prefix (first 4 numbers/letters like 3M51 etc) then the base number (format 12A123 ish) and the first letter of the 2 letter suffix (AA etc). The second letter of this is just the engineering level of the part but if the first letter is different this indicates a different variant.

Course it could be that other level GEMs will work in your car but best getting someone to confirm that before spending your money

Thanks for your fast reply, I think I have found a unit with matching numbers and letters, but they are saying I might have to have the unit coded to my car?? Is this true would I need the new unit to be coded to my car?

Thanks for your fast reply, I think I have found a unit with matching numbers and letters, but they are saying I might have to have the unit coded to my car?? Is this true would I need the new unit to be coded to my car?

It's possible, could be that software and settings specific to your car were downloaded to the original GEM when the it was built.

It's possible, could be that software and settings specific to your car were downloaded to the original GEM when the it was built.

Again thanks for your fast reply, just one more thing, I'm changing this unit coz it's got the rear wiper relay integrated within it (from what I can gather, taking out all the relays and the unit still clicking when the wiper runs) and the wiper won't park correctly. Now could I take my GEM apart and change the relay or woukd it not look like a normal relay as I know it (being an electrician)?

... Oh and I've replaced the rear wiper motor for a brand new one and it still won't park

Honestly don't know if it's possible to replace the internal relays of the GEM - could be worth a look but then it could be hard actually sourcing a replacement relay depending what detail is on it's housing. Could even be a solid state part, never seen inside the guts of a GEM.

Similar issue cropped up when I googled the GEM relay

http://www.fordownersclub.com/forums/topic/34620-ford-focus-rear-wiper/page-3

seems very early mk2 relays had an external relay for the rear wiper but remember now that Ford updated the GEM around December 2005 as other things like the headlamp wash strategy were changed too.

Oh well, I think I will just have to "put up with it" and keep flicking until it's parked. Would it be an mot point?

Rear wiper is not apart of the mot test

... Oh and I've replaced the rear wiper motor for a brand new one and it still won't park

Before you go replacing the GEM/ Fuseboard or try to get inside it to replace the relay recheck your diagnosis.

I think you will find you have a permanent 12v missing from pin 3 on the rear wiper connector (Orange/Blue) wire. It is this voltage that is used to return the motor to its parked position.

Before you go replacing the GEM/ Fuseboard or try to get inside it to replace the relay recheck your diagnosis.

I think you will find you have a permanent 12v missing from pin 3 on the rear wiper connector (Orange/Blue) wire. It is this voltage that is used to return the motor to its parked position.

If the blue/orange wire has lost its feed, where is it feed from?

See this post for the wiring diagram

http://www.fordownersclub.com/forums/topic/42898-ford-focus-full-wiring-schematics-mk225-and-mk3/