A/C blower stopped working?

RHENSONSR

MEMBER
1999 LINCOLN NAVIGATOR
5.4L
V8
4WD
AUTOMATIC
285,000 MILES

I have the Auto Temp Control panel. Pulled the plug on the motor, hooked up 12V and it spins great. Removed the regulator and checked the 3 wires coming from the loom and it had no voltage. 2 fuses and the relay are good. Is my next move to replace the dash control unit? Thanks

Saturday, July 8th, 2023 AT 9:25 PM

3 Replies

JACOBANDNICKOLAS

MECHANIC
110,176 POSTS

Hi,

I attached a pic below from the wiring schematic. Let's check it this way. First, confirm the two fuses are good and have power to and from them.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Next, with the key in the on position, check pin 86 of the blower relay for power. If it has power, turn the HVAC on and see if there is a ground path provided by pin 85.

If that checks good, then check pin 87 for power. It should have power regardless of the key position.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Do this and let me know the results.

Take care,

joe

See pic below.

Image (Click to make bigger)

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Sunday, July 9th, 2023 AT 9:11 PM

RHENSONSR

MEMBER
2 POSTS

Thank you for your reply. I went to the yard and pulled a dash unit from a 2000 model, and it worked. Seems there was a problem in the head unit and thankfully my A/C is working again.

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Tuesday, July 11th, 2023 AT 10:21 AM

JACOBANDNICKOLAS

MECHANIC
110,176 POSTS

Hi,

Thanks for the update. I'm glad you were able to find one and it worked. And I agree. Something was likely shorted in the head unit.

Take care and feel free to come back anytime in the future.

Joe

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Tuesday, July 11th, 2023 AT 7:39 PM