Having problems with your 1999 Mercury Sable ?

FIZZERDAN...........help transmission doesn't want to shift

\015 When was the transmission rebuilt and was it done by a shop with a warranty? I have yet to see an alternator cause damage to a transmission but there has been stranger things. If the alternator was hooked up wrong or a wire was left off, the system could be loosing power to one of the ECMS. Or one of the ecms could of been damage if the wrong battery terminal was hooked up. That I have seen. For the moment, it sounds like the car is in limp home, which is a safety feature by the manufactures that does not allow the car to be driven. Are there any lights on, check engine light, transmission light ect when the car is running?\015\012-------------------------------------------------------------------------------------------------------\015\012Transmission was rebuilt 5k miles ago, but it was over a year ago warranty elasped (I only put 3-5k miles a year on car normally)... and IT was working properly until I changed the alternator... \015\012\015\012Also, now the Service engine light is on,...it wasn't before. And, also when I do try to drive it ... speedometor stays at (zero) or jumps around crazy.. it only goes at 5 MPH idle.. tachometer goes up but car doesn't shift to next gear.. Reverse is fine....\015\012\015\012Reason I had alternator changed at all is because it burnt out 2 batteries..\015\012\015\012I tried unplugging 3 connectors on computer under driver side dash and waited 15 minutes and plugged them back in and then the transmission worked properly for about 15 minutes or so then started the same problem again.. and I tried to repeat same process again but it didn't work at all the 2nd time and now service engine light is on... \015\012Before battery died back when this all started with alternator etc.. the interior light wouldn't go off so I pulled bulb out and my wipers come on all by themselves once in awhile and sometimes when I use the directional blinker.. not sure if this would have anything to do with the Transmission etc. problem now though.. Wipers still come on by themself.. OH and sometimes light for door open stays on when all doors are closed and sometimes door locks won't work either... this stuff all started before I changed alternator and is still the same also. Thought maybe computer doesn't recognize new stuff and this is why I tried pulling connectors and waiting and plugging back in the computer.. hoping it would reset it all.\015\012But, it's not helping ... although, I don't know how to reset computer and was just guessing with the way I did it...\015\012How can I tell if alternator was put in wrong? You would think it can go in only one way..\015\012Sharon,\015 Posted / edited by AnonymousUser on : 16-04-2018

Answers :

I ll try to break this down because you have a multi issue going on. Lets start at the battery. It is the heart and soul of the car. If I am understanding this, the alternator was not charging which caused the battery to die or do you mean it burnt out the battery because it was over charging? If it was over charging, that will destroy an electrical system and cause all sorts of problems. If it was not charging, you put a great deal of stress on the electrical system but most of the stress will be put on the battery which is why they tend to discharge and not come back "life". If your battery is sound by sound, I mean it passes a load test and holds 12.5 to 13.2 volts, we need to move on. \015\012
\015\012Now that the check engine light is on, have you been able to read the code. Auto zone will do this for free. If so, do you have the code or codes at hand? \015\012
\015\012As far as the transmission, it should be controlled by a TCM. "transmission control module" which is the brains to the transmission. If this has a problem, it can cause the transmission to act up but it works in parallel to the ECM "engine control module". After a good visual inspection, the best thing in this case is to read all the ecm's and get any codes that my be present. That is the first step.\015\012
\015\012Now for your interior lights that will not go off, the wipers coming on when you use the directional blinker ect, it sounds like the loads are using a alternate ground or the BCM "body control module" is acting up. Dirty grounds, loose grounds, missing grounds or green wires are a electrical systems worst nightmare. I don t want to shoot you down, but you have a serious electrical problem going hear. I do not know how much electrical background you have, but that is where you are headed. Like I said start at the battery. Make sure your cable connections are clean, tight and in order. That is the easy spot. Then for the alternator, it should only be a power wire and a exciter wire connection, maybe a ground. If it is providing at least 14.2 volts to the battery and passes a amp/load test, its working and you can move on. One last thing you could try is to disconnect the battery for 5 minutes. Due to age of the car, you might beable to reset everything, clear the codes and see what happens. Best of luck.\015\012
Repair Help & Product Troubleshooting for 1999 Mercury Sable

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