I wanted to go over a good solution for swap harness relays. These relays can also be used for stock harnesses.
What is the problem with the stock relays?
Stock relay connectors are not of a sealed design. GM instead applied this nasty black sealant to try to weatherproof the relay and socket. Many troubles come down to bad relay to socket connections. If this design is no kept on it's hanger the relay base will fill with water when hanging by it's wires.
A better solution
GM used these component relays in the 90s on up. They can be found on 95+ full sized 3800 GM cars
12077867 - SPST 12077864 - SPDT
The gray relay on the left is SPST. The black one on the right is SPDT.
I have never had any issues with the stock relays but do like the ones you are using because of the ease of unplugging them. The stock ones are a pain and like mentioned the black goop is a mess on them...
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07:07 PM
GraterFang Member
Posts: 1387 From: Grants Pass, OR Registered: Feb 2008
I have new style relays that are from a newer GM car and had the rerouted from stock location to over on strut tower by batterie trying to keep all wireing to one side of the car ,88 fan relays are the style i used, the come with new mounting hardware .
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04:03 AM
Jul 6th, 2012
phonedawgz Member
Posts: 17091 From: Green Bay, WI USA Registered: Dec 2009
There is really no reason NOT to use these guys in your swap. The new pins are pennies from Mouser and every GM car from the mid 90's on used these things, so they're super plentiful in even the crappiest junkyards.
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03:07 PM
Dennis LaGrua Member
Posts: 15145 From: Hillsborough, NJ U.S.A. Registered: May 2000
I setup a new power center on my 3800SC swap that utilizes the 03 GTP fuse box that contains the Fan, A/C and Fuel Pump relays. Since everything is already connected to the GTP harness it becomes an easy wiring solution. All you need to do is connect power, grounds, the fan, fuel pump and the A/C request. The remainder of the harness is the Fiero one that connects the gauge inputs, trans switch, etc. The downside is that you end up with a harness that is not quite as neat as a full custom harness. My harness may be the only one made in this fashion but everything works perfectly.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
[This message has been edited by Dennis LaGrua (edited 07-06-2012).]
I took this from another forum but I have had issues in the past with identifying correct pins due to the number differences. Is this correct for our applications?
Assume you are wiring a fan or fuel pump.
Pin 1 would be the fused battery feed to the relay. Pin 2 would be the feed to the fan or fuel pump or other load when the relay was not energized. In automotive applications this is rarely used. Pin 3 Would be the feed to the fan or fuel pump or other load when the relay is energized. This is the most common usage Pin 4 Would be the connection to your switch to activate the relay Pin 5 would be grounded.
Your relay will not be number 1-5. There is a standard for relay terminal numbers. Your pin 1 would be pin 30 Power feed Your pin 2 would be pin 87a Normally open Your pin 3 would be pin 87 Normally closed your pin 4 would be pin 85 Activation feed Your pin 5 would be pin 86 Ground
There are several threads on here on relay wiring. Most relays hav a small schematic printed on the case The 30 87a etc is a standard that most automotive relays follow.
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03:30 PM
phonedawgz Member
Posts: 17091 From: Green Bay, WI USA Registered: Dec 2009
The fan relay wires differently than the fuel pump relay.
The ECM provides +12v on the control lead that runs to the relay to turn on the fuel pump.
You would use a SPST relay for this. A SPST relay does not have an 87A (Normally Closed) contact.
----- Fuel Pump Relay Wiring
Green/White - Switched power from the ECM that provides +12v when the ECM commands the fuel pump to run - Pin 85 - Relay Coil Black - Ground - Pin 86 - Relay Coil Orange/Black - Fused unswitched 20A fuel pump power from the fuse block - Pin 87 - Normally Open Tan/White - Power from the relay to the fuel pump itself - Pin 30 - Movable contact
------
quote
Originally posted by CC Rider:
I took this from another forum but I have had issues in the past with identifying correct pins due to the number differences. Is this correct for our applications?
Assume you are wiring a fan or fuel pump.
Pin 1 would be the fused battery feed to the relay. Pin 2 would be the feed to the fan or fuel pump or other load when the relay was not energized. In automotive applications this is rarely used. Pin 3 Would be the feed to the fan or fuel pump or other load when the relay is energized. This is the most common usage Pin 4 Would be the connection to your switch to activate the relay Pin 5 would be grounded.
Your relay will not be number 1-5. There is a standard for relay terminal numbers. Your pin 1 would be pin 30 Power feed Your pin 2 would be pin 87a Normally CLOSED Your pin 3 would be pin 87 Normally OPEN your pin 4 would be pin 85 Activation feed Your pin 5 would be pin 86 Ground
There are several threads on here on relay wiring. Most relays hav a small schematic printed on the case The 30 87a etc is a standard that most automotive relays follow.
[This message has been edited by phonedawgz (edited 01-03-2013).]
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04:25 PM
Feb 16th, 2013
CC Rider Member
Posts: 2037 From: Cameron Park, Ca Registered: May 2001
Using Darths wiring diagram and the relay pins are identified by letters but I'm using the new type relays that have numbers. Can you tell me if my conversion is correct please.
A = 85 B = 30 C = 86 D = 87 E = 87a
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05:21 PM
CC Rider Member
Posts: 2037 From: Cameron Park, Ca Registered: May 2001
Well rather than trying to translate to pins of a relay that you are not going to be using lets keep it to the ones that you are going to be using.
All wiring from the PCM will go to only the coil wires of the relay. Those pins are 85 and 86. These two can be used interchangeably.
Fuel pump - Green/White - Goes to one of the pins. The other coil pin gets a black wire and that runs to ground.
A/C Relay - Lt Blue (AC request) comes from C203 D and runs to one of the coil pins and also runs to the PCM pin for A/C request. Then from the PCM A/C relay control, a dark blue wire runs to the other pin of the coil.
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12:46 PM
CC Rider Member
Posts: 2037 From: Cameron Park, Ca Registered: May 2001
