2008 Cmax Electrical Fault Gem/ecu - Connector C100 Short Corcuit

[gforce2k]

Hi all,

Really urgently need help please - car won't start.

Background

I have had an ongoing central locking electrical fault with my 2008 2.0 Zetec CMAX.

Up to today I've been able to get round the issue (when locked using key fob the passenger doors seize locked and cannot be opened) by bridging power to PIN slot 16 of Connector C100 in the Passenger GEM / ECU / Fuse Box. Since this started happening we have gotten used to locking the car manually and have done this for months to avoid an expensive trip to the garage.

Today

This morning I found that the locks were seized, either when my son locked the car last night or for some possibly weather related reason, but this time the passenger locks would not unlock using the usual method: earthing PINS 11 & 18 and bridging power to PIN 16 from the large brown connector (don't know the number).

This was bad enough but whilst trying repeatedly to trigger PIN 16 I accidentally touched the wire I was using to bridge power across from the brown Connector to PIN 18. There was a spark and fearing the worst I immediately touched the wire to PIN 16 but whereas before it had made the locks click now there was nothing.

I reconnected everything and the radio light came on but when I tried to start the engine it tried starting but didn't catch so I now have a completely unusable car!

What I've tried

I was hoping it would be a fuse but I have checked all the transparent fuses in both internal & external fuseboxes and can find no blown fuses so I'm stumped. It may be one of the solid plastic fuses or even the entire GEM /ECU unit that's blown but I can't tell and I don;t know how to test for it.

We need this car for work next week, can anyone help urgently please!!!?

Thanks,

GF2k

[supercmaxer]

does the pin c100 connected sit facing the floor when the gem is in its located position ?

Have you taken the gem out completely? Easy to do, disconnect the battery first and then unclip all the plugs and make sure you have radio code, when you have got it out check for any corrosion on the pins, fault design by fords as water gets in to it.

I Beileve the large brown one provides all the power so do that after you have disconnected the battery.

If I remember I had a problem with that pin connector, it wouldn't sit in its position and was causing shortage. Make sure that they clip in tight and then move the catch to lock it in to place.

You could use electrical contact cleaner to clean the pins as I did.

When you put it all back I would connect the c100 pin first

[gforce2k]

does the pin c100 connected sit facing the floor when the gem is in its located position ?

Have you taken the gem out completely? Easy to do, disconnect the battery first and then unclip all the plugs and make sure you have radio code, when you have got it out check for any corrosion on the pins, fault design by fords as water gets in to it.

I Beileve the large brown one provides all the power so do that after you have disconnected the battery.

If I remember I had a problem with that pin connector, it wouldn't sit in its position and was causing shortage. Make sure that they clip in tight and then move the catch to lock it in to place.

You could use electrical contact cleaner to clean the pins as I did.

When you put it all back I would connect the c100 pin first

Thanks for the quick reply supercmaxer,

Yes c100 faces the floor when unit swung up and locked into position

Yes all taken out today and have done so before and cleaned, definite water ingress at some point in the past, dirty water smears across the plastic cover

Had the loose connector problem too some time ago so always make sure firmly locked into position

Don't have any electrical contact cleaner - anything else do? prob going to Halfords later if not.

C100 is usually either 1st or 2nd that i reconnect, the brown is always last more because it's awkward than anything else.

[gforce2k]

UPDATE

I have disconnected the battery - took an age, very fiddly, leaving it for 30mins

Also, when disconnected I used my rather crap little rapitest electrical test meter to test across the fuse contacts that I could get to in the engine bay fuse box and found Fuse 3 blown which is a 60 Ampere rating and is 'Passenger junction Box Supply 1' so hopefully that's my problem.

Only trouble is it's not a standard fuse that i've ever used before it's about 3-4cms long with a small yellow transparent plastic fuse cover in the middle and 2 flat metal tongue shaped connectors 1cm wide, each with round holes at each end to allow fastening to vertical bolts sticking up out of the fuse bed.

No idea what the fuse type is called but trip to Halfords will hopefully sort that.

What I'm dreading is if that's not the only blown fuse I'll only found out once i've reconnected everything which may leave it too late to go back to Halfords.

How do I check the solid plastic fuses before i go? they each have 4-5 connectors so i don't know which ones to connect to.

Any thoughts?

Thanks,

GF

[supercmaxer]

UPDATE

I have disconnected the battery - took an age, very fiddly, leaving it for 30mins

Also, when disconnected I used my rather crap little rapitest electrical test meter to test across the fuse contacts that I could get to in the engine bay fuse box and found Fuse 3 blown which is a 60 Ampere rating and is 'Passenger junction Box Supply 1' so hopefully that's my problem.

Only trouble is it's not a standard fuse that i've ever used before it's about 3-4cms long with a small yellow transparent plastic fuse cover in the middle and 2 flat metal tongue shaped connectors 1cm wide, each with round holes at each end to allow fastening to vertical bolts sticking up out of the fuse bed.

No idea what the fuse type is called but trip to halfords will hopefully sort that.

What I'm dreading is if that's not the only blown fuse I'll only found out once i've reconnected everything which may leave it too late to go back to halfords.

How do I check the solid plastic fuses before i go? they each have 4-5 connectors so i don't know which ones to connect to.

Any thoughts?

Thanks,

GF

Hi, unfortunately I don't know how to check the fuses. Think they might be ford only stock.

Have you taken apart the gem? There are clips around the unit I did mine and cleaned all the circuits. I wouldn't use wd40, I only use electrical cleaner cheap as chips from Halfords

[jeebowhite]

If its not a standard fuse, then you are best off going to Ford for a replacement, but yeah you probably blew that when you tripped the spark.

I think you were lucky if thats all thats gone wrong!

[simcor]

Sounds like you have blown either a megafuse or a midifuse, they are very hard to get hold of, best bet is either Ford direct or a breakers yard.

[simcor]

Oh and the solid plastic fuses with 4 or 5 pins you refer to are relays not fuses.