DME Relay Failure - I think it's the diode not the solder points.
#1
Burning Brakes
Thread Starter
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Hey Guys,
So it begins, my first time getting stranded in the P.
Luckily I was relatively close to home and was able make up a 3 way jumper and get the car back into the garage. Once I got the car home I opened up the relay to inspect it and hopefully fix a bad solder point.
Unfortunately from my diagnosis it looks like all the solder points are fine. I inspected them under a magnifying glass and tested for continuity across them and I didn't come across any issues. Where I did have a problem was when I connected a 12V power supply across terminals 85b and 87 of the relay. Using a multimeter I took take a resistance reading across terminals 30 and 87b and got infinite resistance. It's worth mentioning that my relay is the updated 993.615.227.00 part number.
After poking around a little bit more I narrowed it down to the diode at the top of the relay. When testing it with a multimeter (using the ->+ function) I got a voltage drop of 0.115. When I did the same test on the exact same diode at the bottom of the relay I got a reading of 0.001.
So I'm going to order a new replacement DME relay tomorrow (I'll get the 993 part number) but I would like to use this relay as a spare. Does anyone have any suggestions on replacing that diode? More specifically what kind of diode do I need? It's relatively accessible so I should be able to get it with some time and patience.
TIA!
Martin
So it begins, my first time getting stranded in the P.
![Frown](https://rennlist.com/forums/images/smilies/frown.gif)
Unfortunately from my diagnosis it looks like all the solder points are fine. I inspected them under a magnifying glass and tested for continuity across them and I didn't come across any issues. Where I did have a problem was when I connected a 12V power supply across terminals 85b and 87 of the relay. Using a multimeter I took take a resistance reading across terminals 30 and 87b and got infinite resistance. It's worth mentioning that my relay is the updated 993.615.227.00 part number.
After poking around a little bit more I narrowed it down to the diode at the top of the relay. When testing it with a multimeter (using the ->+ function) I got a voltage drop of 0.115. When I did the same test on the exact same diode at the bottom of the relay I got a reading of 0.001.
So I'm going to order a new replacement DME relay tomorrow (I'll get the 993 part number) but I would like to use this relay as a spare. Does anyone have any suggestions on replacing that diode? More specifically what kind of diode do I need? It's relatively accessible so I should be able to get it with some time and patience.
TIA!
Martin
#3
Addict
Rennlist Member
Rennlist Member
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Martin,
Would you kindly share the part number? I'm lazy today, I admit it. I have to order a extra fuel pump relay for my 911SC and a trim piece for my 993 so I may as well get a DME relay, also.
Thank you.
Would you kindly share the part number? I'm lazy today, I admit it. I have to order a extra fuel pump relay for my 911SC and a trim piece for my 993 so I may as well get a DME relay, also.
Thank you.
#4
#6
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so I am having an issue where the car tries to start, but does not. I have 2x DME relays, original and a newer one from a few years ago. I keep both in the car.
On really hot days, or wet days, this seems to happen. I have gotten in the practice of removing the DME, and hitting it on the ground a few times, which seems to work, but not immediately. I was at AX last weekend, and it would not start for a few cranks, even after the hitting the relay. I am wondering if its just coincidence with the relay, and masking some other electrical issue.
My battery is most likely 5 years old, would that also be a potential issue in this case?
On really hot days, or wet days, this seems to happen. I have gotten in the practice of removing the DME, and hitting it on the ground a few times, which seems to work, but not immediately. I was at AX last weekend, and it would not start for a few cranks, even after the hitting the relay. I am wondering if its just coincidence with the relay, and masking some other electrical issue.
My battery is most likely 5 years old, would that also be a potential issue in this case?
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#8
RL Technical Advisor
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so I am having an issue where the car tries to start, but does not. I have 2x DME relays, original and a newer one from a few years ago. I keep both in the car.
On really hot days, or wet days, this seems to happen. I have gotten in the practice of removing the DME, and hitting it on the ground a few times, which seems to work, but not immediately. I was at AX last weekend, and it would not start for a few cranks, even after the hitting the relay. I am wondering if its just coincidence with the relay, and masking some other electrical issue.
My battery is most likely 5 years old, would that also be a potential issue in this case?
On really hot days, or wet days, this seems to happen. I have gotten in the practice of removing the DME, and hitting it on the ground a few times, which seems to work, but not immediately. I was at AX last weekend, and it would not start for a few cranks, even after the hitting the relay. I am wondering if its just coincidence with the relay, and masking some other electrical issue.
My battery is most likely 5 years old, would that also be a potential issue in this case?
I'd need a lot more details than what you've written, but I'd be looking at the battery & and its cabling, connections, grounds, starter, if its not cranking when you turn the key.
#9
Burning Brakes
Thread Starter
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Just ordered two of the 99361522701 DEM relays from Pelican. They should be here by the end of the week I hope. On a humorous side note the local indy parts shop wanted $65 for the relay while the dealer wanted $130. lol
I bought 2 from Pelican for $80 shipped. :-)
I bought 2 from Pelican for $80 shipped. :-)