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Jay, Nissan Technician
Category: Nissan
Satisfied Customers: 20393
Experience:  20+yrs experience with Nissan & Infiniti Trained & Certified.Currently still working for Dealer
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I accidentally grounded my tpms wire under the dash and now

Customer Question

I accidentally grounded my tpms wire under the dash and now my ac just goes on.
JA: Have you checked your tire pressure? Do you have a tire gauge?
Customer: Yes that's not the problem though. My ac can't be controlled. Stays on even if button is off
JA: What is the model/year of your Nissan?
Customer: 2008 Nissan titan
JA: Are you fixing your Titan yourself? What have you tried so far?
Customer: Yes. Tried fuses but don't know which one controles that. Disconnected the blower motor resistor under the dash and ac goes off
JA: Anything else you want the mechanic to know before I connect you?
Customer: No
Submitted: 11 months ago.
Category: Nissan
Expert:  Jay replied 11 months ago.

Hello my name is ***** ***** thank you for your question.

Do you mean the AC fan comes on if you turn the ignition on? Where was this wire located that you grounded?

Customer: replied 11 months ago.
it comes on when I turn on my ignition. The wire was under my dash driver side right behind the diagnostic port to check trouble codes for your vehicle. It was the tpms wire.
Expert:  Jay replied 11 months ago.

Where was this wire located, under the dash?

Customer: replied 11 months ago.
under the dash. I grounded the tpms wire
Expert:  Jay replied 11 months ago.

Ok.. Well the fan coming on is a indication of control unit failure. If it was a TPMS sensor wire, that would blow out the Ecm or BCM. So are you a shop? Do you have a Scanner that can do CAN communication checks?

Customer: replied 11 months ago.
Not a shop.
Customer: replied 11 months ago.
Can it be the blower motor resistor? If I unplug the wire to that it turns off.
Expert:  Jay replied 11 months ago.

Then I am afraid this vehicle will now require a advanced level scanner to see which control unit failed so it can be replaced. When you do bring it to get it checked, you will need to bring all your keys. Both control units hold the key memory. That is why you need to have all your keys so they can get programmed when the control unit is replaced.

No, it is not a blower motor if the engine radiator fan comes on when the key is turned on. That means there is a control unit failure or communication issue.

Expert:  Jay replied 11 months ago.

Do you have any more questions on this?

Customer: replied 11 months ago.
How much does that control unit usually cost. Could I have blown one of the fuses for those control units
Expert:  Jay replied 11 months ago.

well you certainly want to check all fuses first. If it's a simple fuse, that would be a good thing. As for the cost of the control units, it really depends on which one may have been shorted. If it's a Ecm, the part is around 800, then the cost of labor and programming which is around 2 hours. If it's a BCM, that part is around 4 to 500 and that is 3 hours labor and then that has to be configured and programmed along with all tpms sensors

Expert:  Jay replied 11 months ago.

those are all ball park prices.

Expert:  Jay replied 11 months ago.

If you have any more questions on this, please feel free to ask.

If not, and you're satisfied with my help, please Rate me. That is how I get credit for my work. I hope I have provided you with Excellent Service.

Thanks Jay