electinspector

Last Winter my 89 vette battery is dead in two days, I final find out what the problem is, the heated side mirror is not shutdown with ignition is off or pushing off at the digital a/c heating contral, I has to removed the fuse to heated side mirror from the fuse box! I guess a relay is stuck closed somewhere, can forums member let me know where this relay is located or any replacement parts for this,or any one has the wiring diagram so I could fixed this electrical problem..Thanks...Keith:

86PACER

89's had heated rear view mirrors?

SunCr

Yeah - Cool huh? Never had any need for them and getting that harness back together when you replace the glass means pulling the door panel (don't tell anyone - I just spliced mine back in!). Anyway, what to look for depends on whether it's Manual or Electronic. Either uses the Rear Defogger circuit to light up the Mirrors only the Relay for Manual Controls is built into the Panel (or Defroster Controls) and the Relay for Electronic is behind the Dash above the Programmer which is to the right of and above the accelerator. To tell you the truth, I've never gone looking for it and quite frankly I'd check the defroster grids for power first. If they're not hot (and if I remember correctly it times out after 10 to 15 minutes anyway), something is shorted to voltage between the fuse and mirrors - maybe to the motor control? Pink/white is the hot side, you'll need to yank the door panel.

jfb

Yep, the outside mirrors. Heater comes on with the rear window defogger.

electinspector

When I removed Heated mirrors fuse from the fuses box, the battery is not draining, and all function to both side mirrors is working fine. I don't think is a shorted,otherwise the fuse will go. Do you know where the timer is located ? I try looking for the parts # for the relay or timer to side mirror,no one has the this parts. Is this build inside digital electronic controls? My vette has electronic controls a/c and heating.

electinspector

Heated side mirrors.

WVZR-1

Just a "WAG" but I would think it's shared with the rear window defrost relay/timer part# 16042336 which is NLA since '04. I don't have an '89 FSM to confirm location but it seems logical! Like I mention it's a "WAG"!!

* I didn't see "SunCR" post until after I had posted but his location seems to be on the money. The only thing I see is the "generic" parts illustration that put's it in the vicinity of the programmer!

bczee

check to make sure your under hood lights are not staying on ?

Can86Z51

Common problem(hood lamps/switches) on early C4's. My recollection is that all early Canadian C4's came with heated side mirrors,and heated rear hatch glass, as OEM/standard fitment!?

SunCr

Again, the Heated Mirrors are part of the Rear Window Defogger circuit and if Electronic A/C, the Control Panel signal drives the Relay which then (for the Heated Mirrors) runs to the Heated Mirror Fuse and out to the glass. If the Relay was stuck, the Rear Defog would be on too - but I'd be more inclined to suspect the Dash Controls because it's suppose to remove ground after 10 minutes and not restart until you push the Button again, at which time it runs for 5 minutes. So, if the Rear Defog isn't on, the heated mirrors are getting voltage from some other source and since that harness is in the door, looking for anything that's always "hot" in the door makes sense (at least to me). That would include the door locks and I thought the Power Mirrors, but I just realized that's it's my RAV4 that lets you monkey with Mirrors with the ignition off - on the Vette, the key has to be ON. In any event, I'd pull the Panel and see if the hot wire for the mirror heat hasn't abraded against the hot wire for the door locks or any part of the security system and if so, that's where the juice is coming from when the key is off. The draw remains whatever was designed into the circuit so the fuse isn't going to blow, but it will overwhelm the storage capacity of the battery, so it's dead in a couple of days.

electinspector

I put back the fuse,without turn the ignition on, I could feel both side mirrors is getting warm,then it is the elect controls unit wiring to both side mirrors is bad somewhere,or maybe the grounded wire is rub againt the body in one of the mirror and backfeed the system? so, is possible is the ground wire(-), since the unit or mirrors is alway hot?

jim_hewett

Lets see...do I squeeze in under the OS & look up after wife closes the bonnet on me??? Got a similar problem regarding excessive bat drain...30 amps @ bat bypass. No heat on my mirrors either.

SunCr

With the key off - the only power to the Dash Controls is from the Courtesy Clock Fuse which is there to keep whatever you set it at last in Memory. Even an internal short in the Controls shouldn't bleed that power over to the Defogger circuit. Defogger Relay is grounded by the Controls and the switch side is from the Gages Fuse, which is only hot in Run or with the key on. Once it's switched, power is sent to the Defogger and Heated Mirrors from the Defogger Circuit Breaker. That side is always hot, but the relay shouldn't be on until grounded by the Controls. You need to start your diagnostics by seeing what the Rear Defogger is doing. If it's off, your problem isn't with the Controls or the Relay. If it's on, good probability that something is cooking on that side. So tell us what the Rear Defogger is doing first.

electinspector

I test the plug(pass side) to rear defogger has 12v to ground with key off, this mean heated mirrors and rear defog is hot, I never know this wire is hot and was never plug into defogger!