Relay how to

JeffsLightning · 12-22-2006, 11:47 PM

Anyone have a relay how to for wiring a 30 amp relay for say a fan or pump? Need to get a wiring kit also... thanks

urluzn · 12-22-2006, 11:53 PM

check out painless wirings website,most relays have the diagram on them.You can pic up a relay harness at NAPA.

Grimace · 12-23-2006, 07:43 AM

More than likely you will be using a 5 pin relay, and they are all pretty much the same, and they have numbers next to the pin. I get mine from autozone. They are a/c clutch relays, and are about 35 amps. MR78 is the part number.

Wire it like this:
Pin 30 is from the relay to the item you want to power (fan or fuel pump)
Pin 85 is the power wire to the relay coil. (12 volt switched to power the coil)
Pin 86 is the ground to the relay coil (to complete the circuit for the coil)
Pin 87 is normally closed (when the relay is relaxed, no power, this terminal has continuity)
Pin 87A is the normally open (when the relay is relaxed, this terminal is dead)

When you want the relay to fire and turn on a fan or pump, wire it like this:
30- goes to fan or pump
85- 12 volt switched (ignition source or temp probe)
86- common ground
87- nothing
87A- 12 volt power source

I think I even have a nice ms paint relay diagram for my luv truck fuel pump. Let me see.

Pay no attention to the wire colors. They are for a 79 luvtruck.

Hope this is what you wanted.

JeffsLightning · 12-23-2006, 08:43 AM

Thanks guys...

Patrick · 06-07-2007, 04:52 PM

Very helpful!

Vern · 06-20-2007, 06:53 AM

Scan of the Painless Wiring fan relay wiring:
http://www.nloc.net/photopost/data/6...-178-27569.jpg

Steve83 · 05-03-2009, 12:17 PM

.

12-22-2006, 11:47 PM	#1 (permalink)
JeffsLightning Registered User Join Date: Jan 2000 Location: IlliNOIS Posts: 1,588 View this user's gallery iTrader: 9 / 100%	Relay how to Anyone have a relay how to for wiring a 30 amp relay for say a fan or pump? Need to get a wiring kit also... thanks

06-20-2007, 06:53 AM	#6 (permalink)
Vern Moderator Paid Member Join Date: Jan 2000 Location: Columbia, MO Posts: 2,954 NLOC member #: 0072 View this user's gallery iTrader: 2 / 100%	Scan of the Painless Wiring fan relay wiring: http://www.nloc.net/photopost/data/6...-178-27569.jpg __________________ Black 93 #3181 NLOC #0072 TOTM May 08 LFest4 S/L Winner LFest5 S/L Winner LFest6 S/L Winner '09 NMRA/NMCA Superbowl T/S 13 Sec Winner 12.90 @ 103

05-03-2009, 12:17 PM	#7 (permalink)
Steve83 Bronco Guru Join Date: May 2007 Location: Memphis, TN, USA 38135 Posts: 151 View this user's gallery iTrader: 0 / 0%	. . . . __________________ Walk softly & carry a BIG SIX ! ! ! . . . RIP

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12-22-2006, 11:53 PM	#2 (permalink)
urluzn Registered User Join Date: Nov 2006 Posts: 146 View this user's gallery iTrader: 4 / 100%	check out painless wirings website,most relays have the diagram on them.You can pic up a relay harness at NAPA.

12-23-2006, 07:43 AM	#3 (permalink)
Grimace Homegrown Performance Join Date: Feb 2004 Location: Edmond, OK Posts: 1,463 View this user's gallery iTrader: 8 / 100%	More than likely you will be using a 5 pin relay, and they are all pretty much the same, and they have numbers next to the pin. I get mine from autozone. They are a/c clutch relays, and are about 35 amps. MR78 is the part number. Wire it like this: Pin 30 is from the relay to the item you want to power (fan or fuel pump) Pin 85 is the power wire to the relay coil. (12 volt switched to power the coil) Pin 86 is the ground to the relay coil (to complete the circuit for the coil) Pin 87 is normally closed (when the relay is relaxed, no power, this terminal has continuity) Pin 87A is the normally open (when the relay is relaxed, this terminal is dead) When you want the relay to fire and turn on a fan or pump, wire it like this: 30- goes to fan or pump 85- 12 volt switched (ignition source or temp probe) 86- common ground 87- nothing 87A- 12 volt power source I think I even have a nice ms paint relay diagram for my luv truck fuel pump. Let me see. Pay no attention to the wire colors. They are for a 79 luvtruck. Hope this is what you wanted.

12-23-2006, 08:43 AM	#4 (permalink)
JeffsLightning Registered User Join Date: Jan 2000 Location: IlliNOIS Posts: 1,588 View this user's gallery iTrader: 9 / 100%	Thanks guys...

06-07-2007, 04:52 PM	#5 (permalink)
Patrick Patrick Paid Member Join Date: Apr 2007 Location: Sun Lakes CC in Banning CA Posts: 1,200 NLOC member #: 2389 View this user's gallery iTrader: 1 / 100%	Very helpful!