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00 defroster question

I

IROCthe4.0

NAXJA Forum User
Location
connecticut
The defroster in my 00 doesnt work like normal. If I click the switch it wont stay on, the switch wont stay in the on position. If I hold it down, it works like normal. Ive tried three other switches and it still wont stay on. Any idea what could cause this?
 
That's odd. My switch is a momentary that I click once to turn it on and again to turn it off (both in the same direction and it looks like a toggle switch), I always figured it was connected to some sort of timer module in the dash. If so your module is probably broken, I can't find it in my Haynes manual else I'd try to give more detail.
 
The switch is momentary contact and it starts a relay that should stay on for ten minutes or so, then switch off. So if it works when you press, your relay is not latching. I think the one you're looking for is red. It looks more or less like the other relays and has the same base pin layout, but it is unique. There should be a label on it as well. Probably more expensive than you'd like, so you might consider a junkyard.
 
Awesome, thanks. The pick and pull near me has atleast 12 late modle cash for clunkers XJs so Ill grab one off of those. Its too bad too, all those CFC XJs are in mint shape with low miles, one right hand drive
 
I don't know if this is the cause, but it's something I've been wondering.

AFAIK, when you put on the defrost, the AC kicks in to dry the air and defog the windshield. Also, the AC has a pressure switch to keep it from running when on a low charge.

So what happens if you have a low charge (R12 or 134a) and you use the defrost?

Steve
 
SteveT said:
I don't know if this is the cause, but it's something I've been wondering.

AFAIK, when you put on the defrost, the AC kicks in to dry the air and defog the windshield. Also, the AC has a pressure switch to keep it from running when on a low charge.

So what happens if you have a low charge (R12 or 134a) and you use the defrost?

Steve
Click to expand...

It blows higher humidity air. Still with same volume.
 
For example, on my 89 XJ, the defrost works, but my A/C doesnt. It still works. Rear defrost doesnt use the A/C tho.
 
Just to check, I'm assuming we're talking about the rear defroster and its switch? I assume that, since front defrost simply uses the rotary switch and if the rotary switch works at all, I don't see why it wouldn't stay on, even if it doesn't work.

If not, then cancel what I said.
 
It WAS originally rear defrost, but got hijacked by SteveT.

SteveT said:
I don't know if this is the cause, but it's something I've been wondering.

AFAIK, when you put on the defrost, the AC kicks in to dry the air and defog the windshield. Also, the AC has a pressure switch to keep it from running when on a low charge.

So what happens if you have a low charge (R12 or 134a) and you use the defrost?

Steve
Click to expand...
 
Ok, I replaced what I believe is the defroster relay. Still a no go. I can hear and feel the relay in the fues box click when I hit the switch. However it wont stay on. Fuse is good, Ive tried 3 switches, and a new used relay. What else could it be
 
Make sure you check both fuse 12 and 14. There's one for the defroster itself, and one for the relay. It sounds as if both are all right, but it's worth a check. I'll browse my 99 FSM later if I have time, and see if there's any further troubleshooting info.
 
Apparently, unlike earlier versions that had the relay and timer in a single package, the later ones have the timer built into the instrument cluster, and the relay is simply a conventional relay. It sounds as if the problem is going to be in the cluster timer. I have the 99 FSM, and the testing and troubleshooting is pretty involved, and I think it would be easier to scan the pages than to try to paraphrase. PM me if you'd like further info.
 
OK I have a 98xj with a rear defroster proplem aswell. Searching and found this post. I checked all the fuse # 12 and 14 as stated above a few post then I just went back and checked all of them and they are all good. I went and checked the ones under the hood aswell. Still no luck. If I hit the defrost switch the light comes on and after so many min cuts off as if it's working but no go. any other options?
 
jdogg4 said:
OK I have a 98xj with a rear defroster proplem aswell. Searching and found this post. I checked all the fuse # 12 and 14 as stated above a few post then I just went back and checked all of them and they are all good. I went and checked the ones under the hood aswell. Still no luck. If I hit the defrost switch the light comes on and after so many min cuts off as if it's working but no go. any other options?
Click to expand...
Have you done a continuity check of the heating grid on the window? If the light is going on and staying on for a timed interval, then at least the timer is working. Next step, I think, would be to check for voltage at the hatch, and if there's voltage there, continuity of the grid.
 
Ok check voltage at the hatch................So lets say I sould check where they plug into the glass spots for the grid? or is there another place in the panel I need to be checking at?
 
jdogg4 said:
Ok check voltage at the hatch................So lets say I sould check where they plug into the glass spots for the grid? or is there another place in the panel I need to be checking at?
Click to expand...
Try there first. If there's voltage there, suspect the grid and look for breaks. If no voltage there, you need to start tracing back for a fault, perhaps in the harness where it flexes between body and hatch.
 
my 96 the light won't even come on when i hit the switch...

i did have a blown fuse that i replaced, checked the relay (which i can hear when i hit the switch) and the fuses in the power dist box under the hood...

if the switch is turning on the relay then where do i check next?

it quit working after i filled it with water over the seats...

this is the closest thread that i could find related to this...i don't have a fuse 12 and 14 in the 96

mac 'dang attica orange trail' gyvr
 
If the relay got flooded it could be clicking when you push the button but not latching. Of course it's also possible for the light in the switch to go bad, but that should not affect the operation of the defroster. The next step I'd do is to check for voltage at the hatch, since that's easy and informative. Assuming it's not getting there, I'd go back to suspecting the relay.
 
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