993,951,944

My C4S stalled on I-5. I was at 60+MPH and suddenly
lost power and had to pull over. Repeated attempts to
re-start had failed. Pondering what to do next, I remembered
reading a few discussions on Rennlist about DME relay
problems. So, I removed it and the plastic relay cover
and discovered overheated (open) solder connection.
I had a pair of wire cutters and I removed a section of speaker
wire to make a primitive jumper on the relay. The car started
and I was ready to leave. I was stranded only for about 10 minutes.
(As expected, some worthless piker shouted: "Buy a Jeep"
as he passed by. )

When I got home, I immediately started to investigate the failure.
I also have a 944 and 951. I discovered they have the same
DME relay as in the C4S. Part# 944.615.227.00
I re-soldered the internal relay connections and reinstalled it, with
the plastic relay cover removed. The copper top portion of the
relay got very hot in about 10 minutes! I then tested the 951 and 944
in the same manner -these DME relays also got very hot! <img border="0" title="" alt="[Eek!]" src="eek.gif" />
I re-soldered all the connections and ordered new relays...
...I received the updated relay part# 993.615.227.00.
This relay has a larger plastic housing; however. it has the same size
parts inside with just a few improvements with contacts and solder
connections, otherwise the improvements are minor and fall short of
fixing the problem. The parts supplier said that many are still having
to replace their updated part as well. I tested this new relay and it
also runs very hot! These relays are rated at 12V at 15 amps.
However, from my engineering experience, these contacts appear
to be 7-10 amp rated.

I recommend that everyone inspect their DME relays by removing
the plastic relay cover and inspecting for signs of overheating and to
take immediate corrective action. It would also be wise to keep
the old one as a spare.

I was lucky no one was hurt (including the C4S) as a result of this
DME relay failure. I'm sure many others weren't so lucky...

I am thankful to everyone on Rennlist who has contributed their
experiences and ideas... I shall continue to contribute as well...

All the best,

ERAU-944

yeah, all of my cars have suffered failures of their dme relays. nothing tragic, just a $17 part and a &lt;1 minute fix. no big deal. carry a spare always, thats about all you can do.

-Michael

RobbyK

Where is the DME relay located on an early 944?

89magic98

What did the relay spade connectors look like?

Mine are severely discolored (Blackish/Brown). I wonder if this is a function of the excessive current.

Now, I know that the new relay will fix the problem on the relay contacts, but what about the female connectors on the relay panel itself? Can these be cleaned somehow? Should dielectric grease be used (or could this melt, get runny, and cause a short)?

-Kevin

Fishey

never had problems... hell don't even know were the relay is (I bet I could find it) but regardless

SidViscous

Robby.

Under the dash to the left of the steering wheel is the fuse/relay box. DME Relay is high and second from the left I think. Do a google search plenty of diagrams out there.

David

Jumper wires take 10 minutes. Paper trick takes two, works just as good. If they truly are running hot, maybe a second relay inline with higher capacity could cure the eternal DME Relay problem.

Rich Sandor

Do I have to buy the DME relay from Porsche? Or can you get standard ones from any auto parts store?

89magic98

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Rich Sandor:
<strong>Do I have to buy the DME relay from Porsche? Or can you get standard ones from any auto parts store?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">The DME relay is actually 2 relays (switches) in one box, so you need the Porsche one.

Lots of Porsche suppliers (not just the dealer) sell this relay. (Paragon, Vertex, etc.)

-Kevin

89magic98

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by SidViscous:
<strong>Robby.

Under the dash to the left of the steering wheel is the fuse/relay box. DME Relay is high and second from the left I think. Do a google search plenty of diagrams out there.
</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Use latex gloves (for a better grip) and one finger from each hand to wiggle it out.

When re-installing it, be careful not to push in the female spade receptables on the panel that holds the relay. In other words, make sure that the male spade connectors go into the female spade connectors, instead of pushing them out of the relay panel.

DerSchlechtSpecht

This is why I carry an extra in the glove box. NO JOKE! 20 some odd dollars of insurance goes a long way when you are stranded in the rain with your hot date.

Christian

Chris_924s

Sid and KJP- correct! Second relay from left- top row. I find it easier to remove the bottom row relays first, then tackle the DME relay.
I also carry a spare DME in my toolkit. The new relay I bought in Feb is taller and can be a stubborn removal in the early 944/924S.

I didnt see any overheat evidence when I pulled the original relay and disassembled it- maybe another fault somewhere is causing the "hot" dme relay issue?

any ideas??

MHT

probably running hot due to a fuel pump problem, the relay that powers up the ecu carries very little load, the fuel pump, on the other hand, is a high draw item. The load rises if there is a restriction in the fuel filter or a restriction in the supply of fuel to the pump. The DME relay is the only one I can think of that carries that kind of load any time the car is running, so it's not too suprising that it runs fairly hot.

SANDOVAL

Yep me too... I recently purchased a spare. Many of the guys on 968.net carry one also, as we all know they do eventually fail. I think it is cheap insurance to keep you from being stranded.