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Old 11-07-2010, 08:56 AM
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GM Relay Wiring

Found a nice set of OEM relays on a Blazer in the junkyard, I think these will look good and add a factory flair to my build, question is how to wire them...

There are three relays on a bracket, relays are numbered as follows:
10039961, 10034222 & 10034222

I googled those numbers and found a listing for replacement relays referring to them as:
10039961 - Compressor cut-out
10034222 - A/C control

I also found pin-outs for them here, but sadly, I cannot really understand what the terminals mean, need to know where Input, BAT, Output are and whether they are NO or NC - I guess I can test this but thought I'd ask if anyone knew...

I would like to use them like standard Bosch relays for some basic, ignition/switch controlled high current relay applications like sending battery power to my coil, fog lights, trans cooler, etc.

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Old 11-07-2010, 09:45 AM
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Ok lets use the first picture and 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.

Hope this helped and didnt confuse you more
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Old 11-07-2010, 10:54 AM
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Makes perfect sense, thanks Chet
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Old 11-10-2010, 06:38 AM
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Going through some other materials, and looking at another SPDT relay I have, it looks like the terminal indications are different. I found this pic posted at summit


Which would make:
30 Power feed
86 Activation feed
87 Normally open
87a Normally closed
85 Ground

Knowing this, how do I map the pins on these GM relays numbered 1-5?
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Old 11-10-2010, 07:33 AM
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Quote:
Originally Posted by octanejunkie
Going through some other materials, and looking at another SPDT relay I have, it looks like the terminal indications are different. I found this pic posted at summit


Which would make:
30 Power feed
86 Activation feed
87 Normally open
87a Normally closed
85 Ground

Knowing this, how do I map the pins on these GM relays numbered 1-5?
I posted this above

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
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Old 11-10-2010, 07:34 AM
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the 9961 is a SPST relay NC (normally closed) contacts,
the 4222 is a SPST relay NO (normally open) contacts.

so on both relays:
pin 1 ... term 86 (positive side coil voltage),
pin 3 ... term 85 (negative side coil voltage),
must be wired with pin 1 as positive due to diode across coil, otherwise short circuit results (not a good thing),
pin 2 ... term 30 (positive supply voltage).

next is where the terminals vary
pin 5 (9961 relay) ... term 87a (load to be switched off)
pin 5 (4222 relay) ... term 87 (load to be switched on)

use the 9961 to disconnect a circuit when the coil is powered
use the 4222 to connect a circuit when the the coil is powered
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Old 11-10-2010, 08:00 AM
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Quote:
Originally Posted by octanejunkie
Going through some other materials, and looking at another SPDT relay I have, it looks like the terminal indications are different. I found this pic posted at summit


Which would make:
30 Power feed
86 Activation feed
87 Normally open
87a Normally closed
85 Ground

Knowing this, how do I map the pins on these GM relays numbered 1-5?
I posted this above

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
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Old 11-10-2010, 01:37 PM
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post a pic of the panel
you might be better off with a couple of bosch type relays than adapting the whole panel
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Old 11-13-2010, 11:43 AM
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Quote:
Originally Posted by ween
the 9961 is a SPST relay NC (normally closed) contacts,
the 4222 is a SPST relay NO (normally open) contacts.

so on both relays:
pin 1 ... term 86 (positive side coil voltage),
pin 3 ... term 85 (negative side coil voltage),
must be wired with pin 1 as positive due to diode across coil, otherwise short circuit results (not a good thing),
pin 2 ... term 30 (positive supply voltage).

next is where the terminals vary
pin 5 (9961 relay) ... term 87a (load to be switched off)
pin 5 (4222 relay) ... term 87 (load to be switched on)

use the 9961 to disconnect a circuit when the coil is powered
use the 4222 to connect a circuit when the the coil is powered
Seems I have no immediate need for a 9961 relay, here is a pic of the relay cluster

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Old 11-13-2010, 01:29 PM
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toss em.

all 3 are nc relays with no option to add a no circuit

just buy some nice bosch style relays
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Old 11-25-2010, 03:11 AM
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keep measuring the terminals in pairs with your ohm meter, when you find a pair that show a resistance greater then zero.. problaby somewhere around 300 ohms, you've found the two wires for the coil.

when you find the pair that show a dead short, you've got the normally-closed contacts.

now put 12v on the two coil wires, and you should get a click.. now figure out which pair give you the dead short with the coil energized, there are your normally-open contacts. no schematics needed.
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