junkyarddog

among the many mysteries of my car there is a defrost hatch,however no defrost swith. the harness is in the dash between the trunk release and sub amp on off buttons. the dash panel only has the cut outs for the sub and trunk release buttons the defrost harness is hidden underneath.I'd like to keep an original look and install the appropriate swith but I don't feel like cutting my dash panel,I'll wait until I stumle upon a junked '84 with the three cut-outs I need and the defrost swith.the wires for the defrost grid are dangling from the window. right now I just want to hook it up with a hidden switch and need to know what to tap the wires off of and what the circuit current is,fuses ect. I could figure this out but I'm hoping someones done this before and knows the tricks of the trade.

Tim Burgess

If the factory harness is in place, you could connect up to that. Purple / white goes to the defogger grid, orange / black is battery power & comes from the 30 ampere power accy circuit breaker, pink / black is ignition power & comes from the 10 ampere gauges fuse, gray comes from the cluster lighting circuit, and black is ground. If you do the circuit manually, connect the N.O. & pole contacts of a 30 ampere relay to the orange / black and the purple / white wires, and connect the relay coil to the pink / black wire and the on / off switch. Connect the other side of the on / off switch to the black wire (ground). The grid may be turned on & off with the switch & will turn off when the ignition is turned off, regardless of the position of the switch. The only function that will be missing, compared to the factory switch system, when using this control method, is the automatic grid turn off timer.

Tim

junkyarddog

because I don't have the cosmetics for the right switch,i might just"sneak"the wiring form the switch harness and put it with my other hidden switches under the dash,I wonder if the factory defrost circuit ,like the harness ready to use, is in there??

Tim Burgess

The factory defogger timer circuit is built into the factory defogger switch.

Tim