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Relay understanding help
Hi All,
Trying to troubleshoot my non-functioning ABS system. System doesn't work but no dash warning light. Pump also doesn't pressurize itself when first taking off. Below is a picture of the relay which powers the ABS computer (and I think the pump as well) Am I correct in interpreting the relay diagram as follows: pin 31 - incoming switched power (from ignition, in this case) pin 15 - ground for switched power pin 30 - power from battery pin 87 - power out to ABS computer Thanks for clarifying...
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Jerome Welte '97 Spec Boxster '20 Nissan Titan XD |
#2
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That's how I would interpret it.
ed
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ed 2016 GT4 2005 Lotus Elise 1994 RX-7 R2 |
#3
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30 is battery power.
31 is ground 15 is keyed power 87 is output of relay (from 30) |
#4
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That's how I would interpret it
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David D. '87 Targa - 2021 quickly disappearing... |
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Nobody ever got rich by contradicting matt de maria.
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Barry 18 Carrera cab 15 Macan S |
#6
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Thanks All, especially Matt.
I did some quick testing and the relay appears to be working on the bench, so I'll have to dig elsewhere.
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Jerome Welte '97 Spec Boxster '20 Nissan Titan XD |
#7
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Relays die for three main reasons:
1) the solenoid opens or shorts and doesn't provide the electromotive force to pull the contact arm down. Easy to diagnose and fix. 2) corrosion on the pins and receptacles that will insulate the electric current and voltage. Easy to see and fix. 3) the more sinister and frustrating reason is the mechanical contact pads start to wear and can start to have pitting and cause arcing. These mini arcs can accelerate the degrading of a smooth contact between the two surfaces and build up carbon and crud which will insulate the contacts to some degree. In this case the relay may do really funky things. May work initially and then not...may lower the voltage to the intended recipient and it doesn't work properly, may fuse together and never turn off the voltage to the recipient, etc. You can take them apart and inspect the contact surfaces. If any blackish residue on them it can be cleaned off and it may be healthy for a while...but we're talking brakes here. One of my old electronics teachers told me a long time ago that once the contact surfaces degrade, they continue to reap havoc as the arcing will come back and eventually the relay will fail.
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Steve Potomac PCA Co-CI(retired) 89 944 Turbo Race car 85.5 944 NA son's 2015/2019/2020 944Cup and PCA Nat'l Champ racecar 94 968 1 of 11 Iris blue coupes 92 968 1 of 2 Tahoe Blue Cabriolets 98 993 C2S w/Aerokit II 77 911S Vintage race car project 70 Boss 302 86 Mustang SVO 08 F250 SD Diesel 15 Audi SQ5 "Noel spun! Noel spun! Don't do anything stupid, Dad." -the boy on the radio on the last lap of NASA race as the second place car spins behind me in T5 at Summit Point. |
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