Electrical Question (Relays) - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cali_surfer · 03-13-2003, 12:50 PM

I had a question about relays and was wondering if anyone knowledgeable in auto electronics could help me out. On a relay, what do each of the different lugs do? There is 30, 85, 86, 87, and 87a. I know that a relay is like an electronic switch used to take the load off of a switch, when switching a high draw component like an elec. fan, fuel pump, etc..... but I would like to know how these different wires work. This question pertains to the fact that I just bought a keyless entry system and I'm thinking about wiring up power windows to work with my remote...... and the fact that I'd just like to know how a relay works. Thanks for any help.

PanelDeland · 03-13-2003, 01:21 PM

I can't tell you which is which by the #/letter system you posted, but basically a relay is just an electrically operated switch.It uses a coil that creates a magnetic field to pull in a set of contacts. So on most relays you have a power to the coil(usually powered by a switch or other device). A ground for the coil(self explanatory). A hot for the contacts(this hot could be switched thru the ignition but usually isn't).The other two wires on the relay are a n.c(normally closed,closed when the relay is off). The last is n.o.(normally open,open when the relay is off).I don't have a wiring diagram that's postable but you should be able to find one on the web somewhere.

XXL · 03-13-2003, 02:20 PM

Quote:

Originally posted by cali_surfer
I had a question about relays and was wondering if anyone knowledgeable in auto electronics could help me out. On a relay, what do each of the different lugs do? There is 30, 85, 86, 87, and 87a. I know that a relay is like an electronic switch used to take the load off of a switch, when switching a high draw component like an elec. fan, fuel pump, etc..... but I would like to know how these different wires work. This question pertains to the fact that I just bought a keyless entry system and I'm thinking about wiring up power windows to work with my remote...... and the fact that I'd just like to know how a relay works. Thanks for any help.

85 and 86 are the coil. 30 to 87a is closed when the coil is NOT energized. 30 to 87 is closed when the coil is energized.

I hope this helps.

Kenneth

BobbyK · 03-13-2003, 02:55 PM

Here ared a couple diagrams for you.

BobbyK · 03-13-2003, 02:56 PM

another

03-13-2003, 12:50 PM	#1
cali_surfer Registered User Join Date: Jun 2000 Location: Chico, CA Posts: 1,136	Electrical Question (Relays) I had a question about relays and was wondering if anyone knowledgeable in auto electronics could help me out. On a relay, what do each of the different lugs do? There is 30, 85, 86, 87, and 87a. I know that a relay is like an electronic switch used to take the load off of a switch, when switching a high draw component like an elec. fan, fuel pump, etc..... but I would like to know how these different wires work. This question pertains to the fact that I just bought a keyless entry system and I'm thinking about wiring up power windows to work with my remote...... and the fact that I'd just like to know how a relay works. Thanks for any help. __________________ My engine is stock... trust me ;o)

03-13-2003, 01:21 PM	#2
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	I can't tell you which is which by the #/letter system you posted, but basically a relay is just an electrically operated switch.It uses a coil that creates a magnetic field to pull in a set of contacts. So on most relays you have a power to the coil(usually powered by a switch or other device). A ground for the coil(self explanatory). A hot for the contacts(this hot could be switched thru the ignition but usually isn't).The other two wires on the relay are a n.c(normally closed,closed when the relay is off). The last is n.o.(normally open,open when the relay is off).I don't have a wiring diagram that's postable but you should be able to find one on the web somewhere. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

03-13-2003, 02:55 PM	#4
BobbyK Registered User Join Date: May 2000 Location: Petrolia,Ontario,Canada but working in Port Huron,Mi. Posts: 1,771	Here ared a couple diagrams for you. __________________ 71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE

03-13-2003, 02:56 PM	#5
BobbyK Registered User Join Date: May 2000 Location: Petrolia,Ontario,Canada but working in Port Huron,Mi. Posts: 1,771	another __________________ 71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE



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