Hoping someone can check this on their car for me. I'm trouble shooting a wiring issue with my circuit opening relay and discovered I have resistance in a wire that shouldn't have any.

Attached are pictures of how it should be tested...one lead to the FP terminal on the diagnostic box and the other as shown, at the location with the circuit opening relay (with relay removed). My results show 2.9 ohms resistance, but according to the circuit diagrams in the FSM it should be zero(ref page Z28 of the wiring digrams). Hoping I've located the area of the front harness that has an issue.

Thanks for any help guys.

Steve.

 

I have like 3 ft of snow on the ground so I can't check for you but what position should the ign be in?

 

This is an ignition off test. Just checking resistance so no power should be on. Don't have to disconnect battery either so it's real simple. Just pop out the circuit opening relay and connect as shown and let me know what your meter says. FYI: this is checking the wire that goes to the 1T terminal on your ECU.

Thanks.

 

I get .3 ohms - just went to the garage and tried it .

BTW, nice clear pics, made it easy to duplicate the experiment .

What kind of problem are you trying to track down?

Dale

 

Hey Dale, thanks for the response.

My car will not run with the circuit opening relay installed. I have to install a jumper wire as shown below to get the fuel pump to work and the car running. I've tracked it down to the ECU. My ECU will not close the circuit opening relay at terminal 1T. In trying to solve the problem I found resistance in the wire from the relay to 1T which is wrong and suggests that I have a front harness issue. I'm trying to find out where to "open" the front harness to look for a harness wiring issue. The green relay in the pic is the EGI relay. The case is broke because it won't come out without the help of channel-locks but it functions fine. Anyway, I've run a straight line from this terminal to the ECU and it still will not close the circuit at 1T suggesting that several wires may be involved and preventing the ECU from closing the circuit. BTW, 0.3 ohms is the norm when reading the resistance of a basic wire using a standrad over-the-counter digital meter which is what this test should result in. Also, I'm running a stock ECU.

 

I don't think you should get hung up on resistances. They can be misleading, although you may also be onto something. I'd check voltages first...

I'd double check that one of those lower female spades (the ones not jumpered in the picture) is grounded and that the other has 12V with KOEO.

You can also check for 12V KOEO between terminal 14 on the diagnostic connector and ground.

Also, there's a way to gently remove those relays. You crack the case and moisture can get in them more easily... put some tape on it or something. Use a flat blade screwdriver or pick to reach down and hit the release tab (black, shown in your picture).

 

when you start the car does the ecu pull the control wire for the relay to ground?
does the other terminal on the control side have 12vdc on it during key on?

1(ecu control should be switched ground) 2(12vdc for relay control)
3 (load side i.e. the fuel pump etc) 4(12vdc supply for loads)

you jumpered 3-4 so those are ok
check 1 and 2
does the relay shut when you supply power and ground to the coil side it should click and have continuity?

 

I have confirmed that 12v is supplied to the "positive" side of the coil in the relay when the key is set to the starter position. Source voltage is good. However the ground will not close (i.e. the ECU at 1T will not close the ground). This test is really to confirm that my results are not normal.