Intermittent Key Fob

Joined
Oct 30, 2007
Location
Southern California
TDI
98 Jetta
My 98 (only 410k miles so far) has intermittent key fob operation. Great when it works but often no response at all (more often in the morning but either before or after driving and doesn't seem temperature related nor 12V car battery related).
My 2x CR2016 batteries are strong, measuring 3.25V each. Recently replaced the worn fob housing which at first I thought solved the problem (better mechanical contact to switches) but turns out no change.
So, I suspect the car end is intermittent - anybody know where that is and if it can be replaced? (or other ideas)?
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
So you are asking where the alarm module is inside the car? If that's the case the module is on the left of the dashboard under the light switch.

Remove the light switch and you'll be able to see it back there, white box.

To get it out you'll need to go at it from under the dash at that same point.

Steve
 

RoseBud68

Veteran Member
Joined
Dec 16, 2016
Location
PSL FL
TDI
'99 mk3 Jetta 1.9
Having this same issue...I have an extra alarm module to install this weekend. hope this helps.
 
Joined
Oct 30, 2007
Location
Southern California
TDI
98 Jetta
So it looks like in my case it was the key fob at fault. Although the battery was good, the fob apparently would occasionally not transmit. I think perhaps worse when cool?
I tried a different fob and so far no failures after several days use :).
My 98 Jetta TDI key-shaped fob is listed as having two different possible variations, with different FCC ID. I wasn't sure which mine was because I had replaced the case where it's printed on the back, but when I found the other (working) fob I found the following:
FCC ID=M3GHU01WT
CLARION
The other listed FCC ID for this key fob type is
NBG730956T
 
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