94 mercury tracer 1.9l trans wont shift while headlights are on?
 

. The car shifts great while the headlights are off but when I turn the lights on its stuck in second gear. I can be driving with the lights off and in overdrive it will straight dropout of overdrive and go into second. When I come to a stop I can drop it in to first and it'll let me shift it 1-2 but won't shift out of second.

I thought it might be the battery so I bought a higher CCA but that didn't work. I have to get the book on this car so I can find where all the ground so I can clean all of them.

Could it be a fuse or a solenoid or relay? So please help

You must admit that is a pretty Oddball problem when having the headlights on and off determines how the car is going to shift. Or if it's going to shift at all. without a doubt you have head-scratching electrical problem with numerous possibilities of culprits.

first of all I must tell you I'm scratching my head at the thought of the cars shifting or ability to shift at all has a direct impact on whether the lights are on or off. Unfortunately I had a mid-90s Ford Ranger that gave me fits in the transmission Department. During that time in the nineties the Ford Motor Company used a lot of electronics directly inside the transmission like in the axo d in the Ranger. A lot of the lineup for those years were plagued with transmission problems the majority being electrical. Now the only upside I see to your particular problem is that it's directly correlated to the headlights. Now it's just a matter of having it diagnosed by a reputable and knowledgeable transmission guy. Because no matter if it's a 90s transmission or transaxle from the Ford Motor Company almost always the price to rebuild almost always outweighs the value of the vehicle itself.