Main relay location

Tiny
THEODORE28
  • MEMBER
  • 2007 HONDA CIVIC
  • 1.8L
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 110,000 MILES
M y car won't start after it is being driven. I have to wait for an hour to have it cooled down so I can restart again. I just would like to check on the main relay but I can't find it. Hope you can help me locate it. Thank you
Tuesday, August 4th, 2015 AT 6:39 PM

8 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Hello,

Here is a guide to help test the relay with the relay locations below.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.
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Thursday, August 6th, 2015 AT 6:33 AM
Tiny
LAMAVIZCA
  • MEMBER
  • 1 POST
  • 2003 HONDA CIVIC
  • 1.7L
  • 4 CYL
  • MANUAL
  • 279,400 MILES
Could you please explain where the fuel pump relay is located? I have crank no start and I have decided to make that starting point unless you have any suggestions.
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Friday, July 5th, 2019 AT 7:41 PM (Merged)
Tiny
AL514
  • MECHANIC
  • 4,793 POSTS
Good starting point, but you can check it for power. I believe it is located under the dash drivers side behind a kick panel. Check for power going in and coming out the necessary circuits with key on and cranking. But they go bad a lot.
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Friday, July 5th, 2019 AT 7:41 PM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
Thanks for the input AL514, I found this diagram for you please check it out and get back to us. I also included a fuel pump wiring diagram. Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.
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Friday, July 5th, 2019 AT 7:41 PM (Merged)
Tiny
AL514
  • MECHANIC
  • 4,793 POSTS
So, yes the main relays on Honda's control power to everything, ECM power, fuel injectors, fuel pump, power distribution connections etc. Looks like the wiring diagram should be hot at all times at fuse #8 15A under the hood. Looks like the relays are behind the glove box. One of the relays will have one yel/blk wire coming out. This relay will also have a wht/blk wire where power should be hot at all times. Check for power at the wht/blk wire coming out of this relay (same wire coming from fuse 8). If ok, check for power coming out the yel/blk wires (same relay #1) while cranking. This powers the other, including your fuel pump. The ground for the fuel pump is just a blk wire, diagram says under the pass side seat.
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Friday, July 5th, 2019 AT 7:41 PM (Merged)
Tiny
KEN L
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Great input AL514 :)
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Friday, July 5th, 2019 AT 7:41 PM (Merged)
Tiny
ROBHOPS
  • MEMBER
  • 1 POST
  • 2002 HONDA CIVIC
I have looked all through the internet and even looked at the diagram on this site, but still have not been able to locate the Honda Civic EX main relay. It is not located in the same place as the relay diagram you have on a previous diagram. Is it in the same place as the Honda Civic LX or because this is the EX is it in a different location?

Thank you,

Rob Swanson
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Friday, July 5th, 2019 AT 7:41 PM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
I now give you full list of all electrical components including the main power relay. Here is a test you can use once you find it.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

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Check out the diagrams (Below)

Please let us know if you need anything else to get the problem fixed.

Cheers, Ken
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Friday, July 5th, 2019 AT 7:41 PM (Merged)

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