# John Deere 6600 - Relay in Engine compartment.



## Kc Jorns (Jun 11, 2017)

On my 1970 John Deere 6600; mounted on back of engine compartment there is a "silver box", or relay. #2516-A ; it has three wires and a ground. I did replace this two yrs ago and was working....until now (LOL) ; one large red wire goes into the cab and supplies juice to a lot of things...if I jumper from the hot wire on relay to the red wire then all is well; but how does this thing work? Its simple I think but this $60 relay should not just go bad.....does it need a wire to stimulate it? There are actually two hot wires to the relay...a ground....and the red one that should get hot that goes in the cab. Im lost on this stuff... Please advise.....


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## HarveyW (Sep 15, 2014)

Hello KC,
When you turn the key "on" power is supplied to the relay coil, which creates a magnetic field and pulls the contacts together making a circuit for the big red wire to the cab. If you are not getting power the the big red wire, either the contacts are burned out or the coil circuit is open. When you turn the key "on" do you hear the relay energize with a click? 

My guess is that your cab is pulling a bit more current than it should be, and burning the relay contacts. Check you cab circuits for low resistance to ground.


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## Kc Jorns (Jun 11, 2017)

Hmmmm...sounds possible....not sure on how to check that ?  But I assume this relay should "engage" with the "key on" ?


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## Kc Jorns (Jun 11, 2017)

HarveyW said:


> Hello KC,
> When you turn the key "on" power is supplied to the relay coil, which creates a magnetic field and pulls the contacts together making a circuit for the big red wire to the cab. If you are not getting power the the big red wire, either the contacts are burned out or the coil circuit is open. When you turn the key "on" do you hear the relay energize with a click?
> 
> My guess is that your cab is pulling a bit more current than it should be, and burning the relay contacts. Check you cab circuits for low resistance to ground.


 The only circuits Im aware of is the AC/heater fan and the radio....How do I check this? I will go out and check but pretty sure it is NOT clicking as the RED wire does not get hot when key is on. Thanks.


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## sixbales (May 18, 2011)

Also AC compressor clutch, lights? If you have a DC ammeter, you could check the current draw of the big red wire.

Another thought.....If the cab has a poor (rusted/corroded) ground connection, it will cause current draw to increase. Check it out. Make sure the cab is well grounded to the engine/block


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## Kc Jorns (Jun 11, 2017)

ok...thanks! I will do.... wonder if any of you know the part # of this relay where maybe I can find it online for less than JD ? Thanks.


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