Noticed this morning when driving to the dealer for an oil change that the rear defroster was not working. The dash light came on when the button was depressed - but the back window didn't clear up at all. Since the car is parked outside overnight and is driven very early in the morning every day - the defroster not working is kind of a big deal.

So I mentioned it to the service rep thinking it was the fuse. Later he came to me saying they needed more time to resolve the defroster issue - they noted there wasn't any power going to the back wires but the fuse was good.

I couldn't stay longer because my daughter needed the car to get to school - so I took off with it not being resolved. The rep also mentioned as I was paying for the oil change that possibly it's the relay. Seems reasonable since the car has never been tinted so I doubt there's damage to the rear defroster lines - plus they said there's no power going to the back lines.

Anyway, seems like an quick and easy fix if I can find the part. Is the dealer the only option for the relay? I assume it's near the fuse box. Anyone think it could be something else? Thanks.

 

If there is on, I would start with the relay. It may be easier depending on what type of relay it is to get it from the dealer. Parts stores or radio shack may have the type you need as well.

 

Ok - thanks.

 

Well - there doesn't seem to be a relay for the rear defroster. Oh - and the fuse is definitely good. For something that seems to be a relatively simple design - this sure is baffling. Any ideas?

 

Year model?

Service manual indicates there is a relay for the rear defogger, in the pass. side (end of dash) box. From the diagram it looks to be on the top left side.

"Normally open, type B. There should be continuity betw. the No. 1 & No. 3 terminals when power & ground are connected to the No. 2 & No. 4 terminals."

Hope that helps.

 

Thanks! 02 TL Premium. Too dark to look now but I will check it out later today. I had only looked at the two fuse boxes under the hood - didn't realize there was another inside the car.

 

I looked at the fuse box on the passenger side - end of dash. All I see are fuses. TotaledTL - are you looking at a diagram for this model year (2002)? I also called the dealer parts department and they couldn't find anything on a defroster relay (that doesn't necessarily mean anything however!).

 

Should be for '99s-'03s. I pulled the cover over mine & don't see it either. After looking at the diagrams again I think it's on the other side of the box, opposite side of the fuses. Maybe you have to remove the glovebox for access. Dnload the manual & look at pgs. 22-220, -221, 22-94, & 22-103, -104.

 

OK - I see it in the manual - thanks for the page references! Now I just need to find it. It's dark now - I guess I will try again tomorrow. A flashlight in a cramped garage just isn't as good as daylight when crawling under the dash ...

 

Good luck & report back what you find.

 

Darn this standard time - dark when I left for work this morning and dark when I got home. I still tried to look just now for the relay/fuse box with a good light under the dash and around the fuse panel that's on the end. But I don't see anything. So next step is to take the glove box out and look there. That will have to wait till this weekend. I will report back.

 

Glove box removal is easy. Refer to cabin filter threads for help.
It may be easier to just unmount the box and turn it over.

 

I took the glove box out and still don't see anything. Unless it's behind the plastic "wall" that sits between the glove box and the fuse box. Surely Acura wouldn't bury a fuse or relay box this deep into a car so that you'd have to start taking about the whole car to get to it!

 

It looked like that. See if you can just unmount the box (probl. 2 bolts- ?) & flip it over.

 

Saw this in another thread- sounds useful-

"FYI, the fuse box under the windshield on the passenger side will slide up and off once you squeeze the two tabs on the back-side of the box."

 

Hi, I am having the same problem with my 2002 MDX also. Was there any resolve on this issue?

 

First thing to ask is, is the rear defroster wire attached to the rear window? If so are you getting 12v at the wire back there?

 

Fuse is good, no 12v on the grid, the connection on the grid is ok both sides, tested at the harness in the back door and no 12 v there either.

need to locate the relay, I found the wiring diagram but would really like to get my hands on the entire manual diagrams. I have been looking online with no luck at getting it gratis. Can you help?

 

Download the TL service manual here:

https://acurazine.com/forums/2g-tl-problems-fixes-117/2g-factory-tl-shop-repair-manual-852101/

 

Jean Plouffe has an '02 MDX.

While the basic troubleshooting remains the same, the specific electrical schematics will be unique to the MDX. Jean may have better luck in the appropriate forum.

 

Found the relay on the back side of the fuse box under the passenger side. You definitely have to take the glove box out. In my case the relay is ok, I swapped it with the relay for the front blower and the blower worked fine so I put the relay back. Next is to check the on/off switch to make sure it is sending current to the relay and also check the harness in the back for broken leads.