2006 focus,

The problem started with the left turn signal and the left stop light not working. Diagnostics led to the GEM. Replaced it. Now I have a different set of issues. Both stop lights and turn signals stopped working. Diagnostics again lead to the GEM. No opens or shorts found. Fuses are ok. Any suggestions? 

The replacement GEM was in worse condition than the original unit.

Get a tested fully working GEM and also check all the connector pins and wires to the GEM/Fusebox

9 hours ago, unofix said:

The replacement GEM was in worse condition than the original unit.

Get a tested fully working GEM and also check all the connector pins and wires to the GEM/Fusebox

I concur! In my old Merc I got a replacement SAM installed (Merc equivalent of GEM) It cured the 'fault', but came with a whole new list of issues LOL

If it was just brake lights you could get round that by just rewiring brake lights bypassing the gem.    When you say indicators do you mean all of them, not just rear? Including the tell tale lamps on dash?  And no hazard lights? On my brothers focus we thought indicators weren’t working at all but then found they did work outside just no tell tales on dash and no clicker sound (the clicker sound comes from a loudspeaker in the dash at least it did in his mk2.5 1.8tdci).  When the wipers stopped working we reckon it was the gem.  I rewired the wipers bypassing the gem. Not ideal, single speed , no self parking, toggle switch on dash. But he needed to use the car and in the circs it was the best we could do in the timescale we had. So if the front indicators work but not rear I would possibly run a wire from the front to rear on each side. I know that’s not easy or ideal but it’s possibly easier than messing about with the gem. 

Thinking about this, if you do it my way, using your original gem would be better.  One wire from front indicator to rear. One wire across the back from one brake light to the other. 

15 hours ago, isetta said:

 One wire from front indicator to rear

The GEM unit indicator speed will go in to Hyper-flash

7 hours ago, unofix said:

The GEM unit indicator speed will go in to Hyper-flash

Could this be avoid by adding resistor as simulating impedance caused by bulbs?
Yep, I don't know how broken bulb monitoring is implemented in Focus (mk 1 & mk2, CANbus not involved). 🤪
 

If the internal circuit of the GEM unit is faulty for one of indicators, then nothing you do external to the GEM will be able to alter the flash rate. The unit will not be seeing any resistance on one of the circuits and will therefore will act as if the lamp had failed.