I have a 1999 Expedition that lost an alternator this weekend and now has some issues after replacing it. I limped it home and put a new alternator in it. All seemed well after the install, until yesterday. The turn signals are working intermitently and the dome lights as well as parking lights seem to be flashing or surging slightly. I talked to a family friend that works in the Ford service dept. and he thought the GEM module may be bad. Any help would be appreciated, money is tight these days and $800-$1,000 to fix the turn signals at Ford is more than I can afford.

 

are you having any other signs that the GEM is bad?

The flashing or surging kinda makes me thing that the voltage regulator in the new alternator is bad. Wouldn't be the first time I've had a bad alternator right from the store.

 

I am not sure, the voltage is steady when I check it a the battery. Around 14.5 or so while idling.

 

How old is the battery? If it has a bad cell in it, the new alternator could be having trouble regulating power.

 

The battery is about 10 months old. I got an Interstate for it. Never had any problems with them.

 

just for the fun of it go to your local parts store and ask them to ck your battery and alternator start there if you do have a bad cell it can eat up a new alternator also make sure the battery posts and terminals are clean

 

I had a mechanic friend check it out and the battery is fine as well as the alternator. It does have a pulsating current draw that can be seen at the alternator output that varies by 5 amps. At this point I am thinking of pulling the GEM module and cleaning the connections and see if that helps.

 

5 Amps is a lot of power to be pulsating. Thats more power than many single headlights use. 60Ws of surge could easily fry something, so get that fixed if need be.

 

FYI, the specs for the overly common 9004/HB1 headlamp is 65 watts (1200 lumens) for the high beam and 45 watts (700 lumens) for the low beam at 12.8 volts. This works out to about 5 amps for each high beam and 3.5 amps for each low beam.