Dualrelay question

Gotta love that wiring . . .
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Divers

Dualrelay question

Post by Divers »

So...going thru the troubleshooting again....SLOWLY. I got to step 12. Check voltage input to fuel pump relay of relay set. Connect leads between 88y and 85.

I read 12.55 volts. The test says the test light SHOULD come on (in this case voltage). Two options are given

a. If test light comes on, replace double relay
b. If test light does not come on check fuse and wiring to double relay.


Does option a make sense?
spider2081
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Joined: Fri Jan 27, 2006 11:45 pm
Your car is a: 1981 Spider 2000
Location: Wallingford,CT

Re: Dualrelay question

Post by spider2081 »

I think with the ignition switch in the "start" position you should have voltage between terminals 85 and 88a, and also 85 and 88d. terminal 85 is ground through through the ECU. Terminal 88a is red/black wire from the ignition switch. Terminal 88d is green/black wire to the fuel pump.
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bradartigue
Posts: 2183
Joined: Thu Sep 20, 2007 2:35 pm
Your car is a: 1970 Sport Spider
Location: Atlanta, GA

Re: Dualrelay question

Post by bradartigue »

Divers wrote:So...going thru the troubleshooting again....SLOWLY. I got to step 12. Check voltage input to fuel pump relay of relay set. Connect leads between 88y and 85.

I read 12.55 volts. The test says the test light SHOULD come on (in this case voltage). Two options are given

a. If test light comes on, replace double relay
b. If test light does not come on check fuse and wiring to double relay.


Does option a make sense?
"The light should come on," it says, and then "if it comes on, replace the switch." Huh? It's not the greatest. It means, "you've tested everything in this book to this point and it all checks out, so you've gotten here and this switch is showing good - but it really can't be, because everything prior to this checked out."

As part of this step, check 88y to ground as well, with the ignition on you should have 12v. I think FIAT leaves this out (88y is the fused line from the ignition switch). You've tested 85 to 88y, which is both sides of the power source to the fuel pump. Now if you rotate the AFM door with the ignition ON you should hear the fuel pump running. All of that is more or less contained in what step 12 says; "if all that works (if the light comes on) and the car still won't run, this may be your problem."

Borrow a known good switch before you buy a new one; swap it out, see if it works, then move on. I recognize it is frustrating, but otherwise you'll be throwing new parts in when the issue isn't fully flushed out.
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