sable wagon transmission repaired now electrical problem?

I have a 1998 mercury sable wagon with 92,000 miles on it. The transmission needed to be rebuilt, so I brought it to a local automatic transmission rebuilder. After the repair, the battery would not stay charged and the check engine light came on. I brought it back, and he replaced a vacuum line and the alternator (which was fine before the repair). The engine no longer stalls and the battery stays charged, but now the battery light on the dash flashes in rhythm with the engine RPM, stopping when the RPM is at an idle. The A/C will not come on whenever the light is flashing. I can hear the engine strain anytime the light is on, almost as if there is a short (which might explain why the alternator was replaced). Anybody have any idea what this might be? :uhoh:

Carefully inspect the wires near the alternator and where the transmission mates to the engine. Make sure all the wires are properly attached to the alternator and are secure. Also, check for evidence that any of the wires near the transmission may have been pinched between the transmission and engine block. If any of the wires or wiring harnesses appear to have been pinched, then there is a good chance those are causing your electrical issue.

If you are not comfortable checking these yourself, or don't trust the shop that did the transmission work, take it to another shop and have then check for the cause of the electrical problem.

If they find something that is unquestionably related to the alternator replacement or transmission repair, then take the bill to the shop that did the suspect work and ask them to reimburse you. If they refuse to, then you may wish to send the same reasonable request to the shop through a lawyer.

-Rod

Thanks Rod! I believe you are correct because it makes sense. I was just looking at the battery voltage with my meter and found it jumping back and forth between 17 and 12 volts in sync with the battery light on the dash, then after about a minute of this the battery went to 12 volts solid and the dash light is on permanantly. I think the alternator is cooked (again)! He must have a short as you describe.

We left the car with him for a week for this electrical problem - I would have thought he would have checked it out more thoroughly before just replacing the alternator. Even after he replaced the alternator, it was pretty clear something was wrong with the light going on and off like it did, don't know why he chose to ignore it.

Good luck. Electrical gremlins can be quite difficult to track down. At least with your car you hopefully have have just a couple of areas that the tech can focus on, assuming the problem is related to the tranny service. Of course, there is a chance that the current problem just coincidentally showed up at the same time another system was repaired. :(

-Rod