Add wiper & defroster to back window of 1985 mercury marquis station wagon

any ideas on how i would go about adding a back window defroster and wiper to my 1985 mercury marquis 3.1L station wagon? $500 car from sister’s mother-in-law. car in excellent shape-worth adding these to it.

thanks, in advance, for your help.

It’s quite likely that the car is already wired for the defroster (they’ve been mandatory in Canada since 1968), so that’s likely just a matter of getting back glass with the defroster in it and grabbing a switch from a junkyard. Look around the back window-- there’s probably a blade connector back there that’s not hooked up to anything.

That may also be the case with the wiper, but the wiper was probably a rarer option (was it an option at all?), so it could be that you’ll have to do some drilling to adapt the motor in. A service manual would be handy.

Another possibility is you could just try to find a tailgate at a junkyard that has all the options you want and just swap it in.

sorry it’s taken so long to reply. you’re amazing. i will try all the options you suggested and let you know the outcome. i especially like the idea of just getting a tailgate that already has these options. thanks for your time and help. i love canada. have a good friend from there.

I had one of the wagons some time ago. If you can find a junkyard rear window glass with the defroster intact you might be able to swape it out pretty easily. I expect the wiring is present as Greasy suggests.

The wiper isn’t going to be so easy. The wiring may or may not be there. You need a wiper motor and all the mechanism. Finding a car this old in a salvage yard is going to be a challenge. Most have been crushed a long time ago.

I won’t put much into upgrades, just keep up the maintenance and repairs. You’re going to need some gas money because this car eats a lot of gas but isn’t too bad considering the space you have in it.

By the way never leave the ignition “on” without the engine running. I did this when my car stalled as I was launching a boat. I didn’t restart the motor for about 15 min. as I was busy with the boat and that is all the time it took to burn out the electronic ignition module.

i was hoping (maybe wishful thinking) that some of these cars will show up in junkyards due to the “cash for clunkers” program that recently ran in the States. Worth giving a look.

I feel i need the wiper/defroster for safety reasons. live in midwest-most of the time i can’t see out of the back window due to fog, freezing rain, snow, etc. other than those two things, i am going to remove/repair some of the rust spots and spend the rest of my money on gas. luckily, i don’t drive her much.

thanks for your help and heads up about ignition being left on. wish i had a boat. :slight_smile:

Believe it or not, this car is rated at 18 MPG combined so it didn’t qualify for the cash for clunkers!

I personally have found that rear wipers on wagon-type vehicles with flat back glass aren’t all that useful. Especially if you don’t have a very effective rear washer pump. I’d say if you’re going to spend money making the car more winter-ready, spend it on snow tires-- this car is rear-wheel drive which is going to be a little squirely in the snow.

Adding the rear wiper/defroster to your car is a quick and easy way to double it’s value.


Before wagons had wipers for the back windows we had them fitted with air deflectors that moved some air across the back window. Some of them were useless, but some actually helped you see something out the back window.

Also, once upon a time there were after market kits for rear defrosters. These were stick on wire grids to provide some heat.

If you can find these things you may be able to make it work if you can’t find a junker for parts.

Have you tried Rain-X on the back window?

Google “Used Auto Parts,” Then do a nationwide search for a used rear door with those options installed… Good luck. Oh, you want the paint to match too??

If you’re talking about the Fox-based Marquis, It’ll have the 3.3L I6 or 3.8L V6 or if you have a Canadian model it could have the 5.0L V8, but those are ultra-rare. The wagon it’s pretty rare these days. A rear window defroster would be pretty easy to do, but the rear wiper is going to be more difficult.