Direct wire rear defrost

Tiny
DCKELLEY
  • MEMBER
  • 1998 BUICK PARK AVENUE
  • 3.8L
  • V6
  • 2WD
  • AUTOMATIC
  • 190,000 MILES
I'm wondering if I can bypass the antenna module and directly wire rear defrost? I don't have a lot of cash right now and frankly I listen to the radio rarely. Thanks, Don
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Thursday, January 10th, 2019 AT 9:37 PM

6 Replies

Tiny
ASEMASTER6371
  • EXPERT
Good morning,

No, that would be a bad idea. The rear defogger is on a timed circuit. The antennae is a constant circuit. This means you can overheat the rear window and run the risk of fracturing the glass from too much heat.

Did you check the fuse for the rear defogger?

Make sure the fuses to the HVAC system in the fuse panel have power on both sides with the key on. The control head for the AC module controls the activation of the rear defroster and also controls the time based on ambient temperature.

Roy

The heater and A/C programmer receives the rear defogger request from the heater and A/C control assembly. The heater and A/C programmer will then send a Class 2 message to the body control module (SBM). The SBM will control the rear defogger on/off status and the amount of time that the rear defogger is on. The SBM will communicate the rear defogger status to the heater and A/C programmer over the Class 2 serial data and the heater and A/C programmer will light the rear defogger indicator accordingly.
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Friday, January 11th, 2019 AT 5:44 AM
Tiny
DCKELLEY
  • MEMBER
Thanks Roy, I didn't think about the timer. I did pull the large 40 amp fuse (it looked fine). I'll need to check the one under the dash next.
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Friday, January 11th, 2019 AT 8:15 AM
Tiny
ASEMASTER6371
  • EXPERT
Okay, let me know.

Roy
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Friday, January 11th, 2019 AT 8:17 AM
Tiny
ASEMASTER6371
  • EXPERT
Did you reply? I see you posted but nothing came up?

Roy
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Friday, January 11th, 2019 AT 8:25 PM
Tiny
DCKELLEY
  • MEMBER
I deleted a comment that I meant for my other post. Sorry about that.
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Friday, January 11th, 2019 AT 8:27 PM
Tiny
ASEMASTER6371
  • EXPERT
No worries. Wanted to be sure I did not miss something

Roy
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Friday, January 11th, 2019 AT 8:32 PM

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