andyaubs

Took my hardtop off for the summer this year and ever since putting it back on a month ago, the defroster has not been working. When I press the button and it's staying on, but no activity. It's not the end of the world if I can't use it now, but with winter months and snow approaching it would be useful to have working...

I've checked electrical continuity between the harness and the glass and it seems SAT . Also checked the electrical connection from the wiring forward to the top and it appears ok.

What should I be getting for voltage levels between the glass and ground? Was seeing only ~350mV.. Glass contact to glass contact (side to side) was continuous at near 0 ohms. Anything that will help get me towards figuring this out would be appreciated!

Jiblet

Is the rear wiper working?

andyaubs

Yep working fine! Only defroster not working as normal.

jk_sea

This is purely speculative...electrical really isn't my thing. But if you are able to turn on the switch, but there's no voltage being passed through the grid, maybe a relay is toast? Don't all those sit up in the fuse box?

It's an easy check if you haven't already.

Jiblet

Pretty sure you should get 12v across tabs and across the buss bars (vertical strips). Meant to get out my multimeter today to confirm it on mine but didn't get a chance. I try to get to it tomorrow.

ezdoesit06

Do a basic fuse test and make sure it isn't blown. Also if it has a relay. Replace it with another good one such as the horn and see if that eliminates it. If not then you know it's electrical like a short to ground or something like that

ronjenx

Here is a picture showing the rear defogger relay and fuse.

With the key in the run position, have someone turn on the defogger while you listen for the relay to click.
Check for 12 volts between the two grid contacts.
If you get 12 volts, turn off the defogger, and check for continuity between the grid's negative terminal and ground.

JKU Jay

Sorry to revive an old thread but this one could be a big help now that things are getting frosty. Here's what I have so far.

I do hear the relay click when I turn on the rear defrost.
I do get 12 volts across the 2 grid contacts for the 40A fuse.
With the defroster off I get NO continuity between the neg side of the fuse grid and the battery ground (neg).

Does that mean I have a ground short somewhere? If so, what do I do now?

From earlier in the thread I do have current across the rear defroster busses (side-to-side), the plug shows voltage, and the posts that the plug goes into have continuity.

Thanks in advance.

Jay

pazitive44

Check the pins on the connector to Hard Top ...sometimes they're pulled out a bit and you won't get any power ...is the wiper and washer working ??