Where the @#$% is the Rear Defroster Relay?!

Reply Subscribe

Thread Tools

Search this Thread

Apr 19, 2014 | 08:36 PM

inertian

Thread Starter

Senior Member

Joined: Nov 2007

Posts: 247

Likes: 62

From: Lindenhurst, NY

Where the @#$% is the Rear Defroster Relay?!

My rear defroster has not worked since I've had my car, about 2.5 years. The console switch and dash light come on, but nothing is happening on the glass itself. Switch and fuse are fine, and I would check the relay if I could find it...looked under both sides of dash, cant seem to find the large yellow DAC10020/DAC1328/33383 - TIMER RELAY UNIT, REAR WINDOW DEFROSTER. Anyone know where it is?

Last edited by inertian; Apr 19, 2014 at 08:44 PM.

Apr 19, 2014 | 11:29 PM

Doug

Veteran Member

Joined: Mar 2008

Posts: 25,521

Likes: 11,713

From: Pacific Northwest USA

If it ain't in the LH underdash relay panel I don't know what to tell ya.

Maybe it has been replaced with one of a different color? Pull relays unit the indicator lamp goes out.

Cheers
DD

Apr 20, 2014 | 12:41 AM

malc4d

Veteran Member

Joined: May 2013

Posts: 1,703

Likes: 470

From: Orlando

Says its in the left underdash compartment....

Relay and Fusebox-Driver's Side - Parts For XJS from (V)179737 to (V)226645 | Jaguar Classic Parts UK

Apr 20, 2014 | 03:08 PM

inertian

Thread Starter

Senior Member

Joined: Nov 2007

Posts: 247

Likes: 62

From: Lindenhurst, NY

My car is a pre-facelift, but the diagram indicates LH fusebox as well:

Main Fusebox Mounting Plate Relays - Parts For XJS from (V)139052 to (V)179736 | Jaguar Classic Parts UK

I basically pulled and cleaned every relay and corresponding wire I could find under both sides of the dash, figured it couldn't hurt. I definitely hear the click of a relay (under the left side) when I engage the Rear Defrost control and dash indicator light comes on.

BTW, how long should the Rear Defrost stay on before timing out? Mine stays on until I either shut off the car or switch it off manually. Today I took a drive for about 30 minutes and the dash indicator light was on the entire time...but no temperature change in the rear window as far as I could tell. Is that indicative of a bad relay?

Apr 20, 2014 | 04:29 PM

Doug

Veteran Member

Joined: Mar 2008

Posts: 25,521

Likes: 11,713

From: Pacific Northwest USA

Not sure about the XJS but.....

The Ser III XJ sedans (and possibly others) could have a regular relay or a timer-relay in the socket. Some had one, some had the other....the socket accepts either one. Since yours never 'times out' I wonder if it the timer-relay has been replaced with a regular relay?

Use a voltmeter or test light to see if you have voltage on the rear window grid and/or visually check for broken grid wires...including the tabs at the edge of the glass where the harness wires attach

Cheers
DD