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944 DME Relay Bypass

Posted: Tue Mar 24, 2026 3:17 pm
by Tom
Just finished building out a 944 Relay Bypass page for the 944 Handbook, continuing our effort to make the 944 Handbook and updated and comprehensive guide for 944 owners. :) The emphasis is on easy reference, with strong visuals, so you don't have to hunt through a 20 page thread while stranded on the side of the road. The guide is now live and can be found here.

DME-Bypass-Visual.jpg
DME-Bypass-Visual.jpg (477.21 KiB) Viewed 257 times

Re: 944 DME Relay Bypass

Posted: Tue Mar 24, 2026 7:47 pm
by whalenlg
Nice write up!
I keep a spare dme relay AND the 3 way jumper in the glovebox. Can’t have enough redundancies!

Re: 944 DME Relay Bypass

Posted: Tue Mar 24, 2026 8:51 pm
by 944er
The correct solution is to carry a spare DME relay, AND a three wire jumper. My jumper has the pins identified with little flags, but someone on the forums pointed out to me that the three pins to be jumpered are all the larger pins, so not hard to identify.

Replace the relay (and carry on,) if not, use the jumper (and get home,) and if no bueno, call the tow truck. These are old cars, and ownership, regardless of the fun level, carries the possibility that it isn't going to make the trip. My car has never failed to make it back home, but I fully accept that this is a possibility. It has, however, failed to start three times since new, always due to lack of use. Twice due to a completely failed battery that could not be revived, and once when all four injectors were stuck. It has started a several times, and recovered within a minute or two, with one or two stuck injectors. It is getting more periodic use these days, every month or so, so no stuck injectors in a long time.

Re: 944 DME Relay Bypass

Posted: Tue Mar 24, 2026 9:20 pm
by Tom
Both your replies make me want someone to start a "Things to carry in your 944 to avoid getting stuck somewhere" thread... I've been stuck twice in mine in 25+ years -- once thanks to an aftermarket alarm (now gone), and once when heavy rain soaked the DME via an unknown to me rust hole under the battery (also gone now).

p.s, great point about the jumper going into the 3 wide spades -- I'll add that in the morning assuming that's ok with you. :angel:

Re: 944 DME Relay Bypass

Posted: Wed Mar 25, 2026 5:07 am
by barnwerks
Great work on this Tom! If you're editing, perhaps add a note about fusing the jumper and/or to connect to the 30 terminal last and disconnect from it first to prevent accidentally connecting battery voltage with the chassis.

Re: 944 DME Relay Bypass

Posted: Wed Mar 25, 2026 10:16 am
by Tom
barnwerks wrote: Wed Mar 25, 2026 5:07 am Great work on this Tom! If you're editing, perhaps add a note about fusing the jumper and/or to connect to the 30 terminal last and disconnect from it first to prevent accidentally connecting battery voltage with the chassis.
Updated it just now for that point and the wide-spade point. Great comments, thank you!