1998 Ford Taurus Transmission shifts erratically with air c

Tiny
ERIKMANLEY79
  • MEMBER
  • 1998 FORD TAURUS
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 118,000 MILES
Hello everyone,

I am new here and am having a strange problem with my 1998 Ford Taurus.

Awhile back I noticed that the car would act as if it lost power for a split second whenever I would be driving and then turn on the air conditioner.

It is something that I could not reproduce every time I tried it.

What would happen is that after driving the car with the air off for any decent distance I would switch on the air and then right at that moment the car would stall, the gas and other error lights on the dash would come on, and the radio would flicker off.

It only did it for a second and then would be fine but normally I would turn the air back off to be on the safe side.

The latest thing that I think is related is that now when I drive the car anywhere from a mile to 20 miles with the air on, eventually the transmission acts like it's goes nuts.

The car will feel like it downshifting before it should, it will rev up, and sometimes it feels like it wont shift up even though I am pressing on the gas pedal. The only way to get it to stop is to turn the air off and then everything is ok.

The only hint of a solution that I have found is that I may need to replace my transmission speed sensor (sorry if I got that part name wrong), because the air conditioner when on, is messing with it and the car doesnt know when to shift.

That was a really long post but I wanted to try to cover everything I could, thanks for any help you can provide.

Oh I almost forgot, the car is not kicking out any codes and the check engine light is not and has not been on this whole time. Also I had the battery and alternator checked and the store said that those parts are all fine.

Additionally, the transmission fluids are normal (no smell, proper levels, clean).
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Wednesday, July 14th, 2010 AT 10:47 AM

10 Replies

Tiny
KHLOW2008
  • EXPERT
Hi erikmanley79,

Thank you for the donation.

From the symptom description, I believe that the problem is most likely due to a poor ground circuit. Somewhere the wireharness is not getting sufficient ground and when the A/C is turned on, excessive power surge/drain occurs and that would cause the hesitation.

Was any repairs done prior to this occurring?
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Wednesday, July 14th, 2010 AT 12:34 PM
Tiny
ERIKMANLEY79
  • MEMBER
Before the escalation of the symptoms happened (weird shifting with the air on) and it was just sort of losing power for a split second, the only work that I can think was done to the car was an oil change and a mechanic fixed the mechanism that pops the hood. This was my mothers car so I will have to ask if there were any repairs that I was not made aware of.

Your answer at least gives me something to try to look for which is more than I had before lol. Do you have any suggestions on areas I should check such as driver or passenger top/bottom etc? Would running a new ground wire from the battery help?

"Replace the transmission range sensor. Ford runs all the grounds for the circuits you mentioned through that sensor. The power steering pressure switch grounds through the sensor also. It is fairly easily replaced and relatively inexpensive. Somewhere around 50$ I think. Good luck and let us know."

Could this sensor be going out and be a good place to start in addressing a ground issue?
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Wednesday, July 14th, 2010 AT 11:07 PM
Tiny
KHLOW2008
  • EXPERT
From the link that you supplied, yes, that would be a good place to start as the symptoms could be related.

The transmission Control Switch is located on shifting lever, on steering column.
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Thursday, July 15th, 2010 AT 9:04 AM
Tiny
ERIKMANLEY79
  • MEMBER
Is there also a transmission range sensor a.K.A. Neutral safety switch, that is attached to the transmission somewhere? I think I read some posts about this and that it was easy to replace but I cant seem to find a decent answer on where it is at on the 1998 ford taurus. I figured I would replace the cheaper of the two parts (control switch and the range sensor aka neutral safety switch) and then if needed do the other.
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Thursday, July 15th, 2010 AT 1:22 PM
Tiny
KHLOW2008
  • EXPERT
Sorry for the misunderstanding.

The transmission control switch is the same as the PNP or range switch.
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Thursday, July 15th, 2010 AT 1:58 PM
Tiny
KHLOW2008
  • EXPERT
Yes, that is the part you should be looking for but for different year model, the location is different.
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Thursday, July 15th, 2010 AT 2:38 PM
Tiny
ERIKMANLEY79
  • MEMBER
I think I just found it, it looks like it is at the top driver side with some linkage attached to it and the wire harness. The shape and everything matches the aprt on autozones website so that should be it. Thanks for the help, I will order the part today and see how it works. One last thing. I read on a forum that ford recommended disconnecting the wire harness from this sensor to to see if the problems go away, purely as a test. Does this sound right to you?
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Thursday, July 15th, 2010 AT 2:45 PM
Tiny
KHLOW2008
  • EXPERT
That depends on the problem that you are experiencing and for the symptoms you are experiencing, it might not show anything. Anyway there is no harm trying.
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Thursday, July 15th, 2010 AT 3:18 PM
Tiny
ERIKMANLEY79
  • MEMBER
I am heading to the store to order that part and will make sure to leave ya some positive feedback shortly. Hopefully I wont have to add any more questions to this thread after the next few days (as I cross my fingers lol)
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Thursday, July 15th, 2010 AT 4:53 PM
Tiny
KHLOW2008
  • EXPERT
Good luck. :)
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Friday, July 16th, 2010 AT 7:14 AM

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