Wire Rear Defrost into Front?

[MikeyMike]

ya is there anyway to wire the rear defroster so it comes on with the front?

Caz when i get out of my car @ night i put the front one on so when i autostart it in the morning, i can get right in & drive to work. the front window is nice & clear, and the car is all nice & toasty, but the rear window is always frozen solid. I wanna wire it in so it comes on when the front one is on, that way when i autostart in the mornin it will defrost the rear as well.

 

[DizzyP]

Bump. I been thinking of the same thing. Far as I know the rear defroster is a latched relay so pushing the button activates the relay and it stays on for about 20-30 minutes before auto turning off or unless the car is turned off before that then the rear defroster turns off. I have a Viper 550 alarm with remote start and it would be nice to have the front and back defrosted and getting into a warm comfy car but for now I just have the front. I was considering installing a relay to a temp monitor AND and timer so the rear defroster would come on every hour or so for about five minutes if the outside temp was below 40 degrees while the car is not running but still looking into power drain. Also included in this set up would be a low voltage cut off so if the voltage goes below 11 volts it would disable the auto rear defroster hook ups along with 12 volt accessory port which I plan to make hot even with key out the ignition. Any one have any ideas?


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[Turbo5upra]

I would simply find out if the trigger out of the switch is positive or negative- tie that wire to an unused output on the remote starter and be done.

A 5 minute 2-300 watt drain 6 or 8x a night is simply going to drain the battery with no real gain- even if there is Ice on the window one 15 min cycle should make it brush right off. (I use the above method on my cars)

 

[DizzyP]

I think I will do it your way and see if I am happy with it. Don't get snow in Sacramento just frost. In the cold months I set my remote start for 5 min which is just enough to get the interior warmed up. Summer months I set it to 12-15 minutes depending on weather. Since cold months it doesn't dip to below 40 for more than a few hours a night so it wouldn't be too much of a battery drain plus the low voltage cut off would help prevent it from not being able to start the car in the morning. Thanks.

Oh, you got a tip on which wire to tap into or should I just go to the Google Machine to figure it out? Any other tips would be helpful too. Thanks again.


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[Turbo5upra]

http://www.6thgenaccord.com/forums/showthread.php?t=40232 if that doesn't work lmk. Be sure to test it.

 

[FNCONE]

** I posted these on another thread.**
Try these wires on your remote start.

Guys here are the diagrams for auto and manual control. Looks like B7 From the Auto climate Brown/Yellow Controls The relay for the rear defrost. On the Manual climate pin 4 also Brown/yellow controls the relay for the rear. These wires might be your best bet since it is a timed circuit.

Auto Climate



Manual AC

 

[FNCONE]

If it can be tapped into, hopefully the button (internal signal) is not needed just a signal (externally, like the alarm remote start) to activate the relay.

 

[DizzyP]

Thanks for the diagrams. Now ya got me thinking. I might just hook up a 555 timer or the likes to be hooked up to the FRONT defroster that would either give it the pulse or constant electricity needed to activate the rear defroster. The reason is if I leave the front defroster on when I turn the car off it will turn back on when I start the car and I usually want the rear defroster on when the front one is going. That way I won't have to program the alarm again.


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[DizzyP]

Decided to run it separate from my remote star and front defroster. It runs if weather is colds and stays on for 15 minutes then auto shuts off.


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[DizzyP]

I recently hardwired my module to the circuit board so now when ever my timer is running the rear defroster my factory light comes on instead of a separate LED.


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