retro 4,048 Posted June 3, 2021 Ok good, I have another test that I am trying to figure out on a spare wiring harness that I have. Be back in a bit. Go ahead Mel if you have anything for him. Share this post Link to post Share on other sites
Melatv 792 Posted June 3, 2021 Key off -- 16p ECM connector (harness side) check for continuity Bl/O to neg. of battery = what? Key off -- 16p ECM connector (harness side) check continuity O to G/Bu wire = what? Share this post Link to post Share on other sites
retro 4,048 Posted June 3, 2021 4 minutes ago, Melatv said: Key off -- 16p ECM connector (harness side) check for continuity Bl/O to neg. of battery = what? Key off -- 16p ECM connector (harness side) check continuity O to G/Bu wire = what? According to the wiring diagram I am using that test should read: Key off -- 5p ECM connector (harness side) check for continuity Bl/O to neg. of battery = what? Key off -- 5p ECM connector (harness side) check continuity O to G/Bu wire = what? 1 Share this post Link to post Share on other sites
Melatv 792 Posted June 3, 2021 Yes that's the 5P ECM connector not 16P ECM connected Share this post Link to post Share on other sites
Melatv 792 Posted June 3, 2021 1 minute ago, Bossdaddy said: 16 p plugged in? NO Share this post Link to post Share on other sites
retro 4,048 Posted June 3, 2021 I think we are chasing the same thing right now Mel.... I was trying to figure out a test (using a spare wiring harness that I have) that would verify that the ECM is activating the relay coil through the Bl/O wire and also test that the relay is transferring battery voltage from the R/W entering the relay, to the R/Y exiting the relay. I didn't come up with a test solution that doesn't involve poking through the insulation of those wires though.... 😞 1 Share this post Link to post Share on other sites
Bossdaddy 209 Posted June 3, 2021 16 p unplugged, 5 p bl/o to bat neg reads 105, o to g/b reads 0.00. 1 Share this post Link to post Share on other sites
Melatv 792 Posted June 3, 2021 3 minutes ago, Bossdaddy said: 16 p unplugged, 5 p bl/o to bat neg reads 105, o to g/b reads 0.00. That's good -- both of us doing some heavy thinking now Share this post Link to post Share on other sites
Bossdaddy 209 Posted June 3, 2021 If we need to poke holes that’s ok I can repair insulation. 1 Share this post Link to post Share on other sites
Melatv 792 Posted June 3, 2021 My night to cook supper -- check with you later 1 Share this post Link to post Share on other sites
retro 4,048 Posted June 3, 2021 Yup! Thanks Mel! Shouldn't the Orange to Green/Blue continuity test measure resistance though, rather than 0.00 ohms, since that test measures resistance through the shift motor? I would guess that the shift motor should measure a few ohms resistance? 1 Share this post Link to post Share on other sites
Bossdaddy 209 Posted June 3, 2021 I will ck it again 1 Share this post Link to post Share on other sites
Bossdaddy 209 Posted June 3, 2021 Meter set on 200 1 meter reads .5 another meter reads 1.2 2 Share this post Link to post Share on other sites
retro 4,048 Posted June 3, 2021 Well I just checked resistance through a shift motor that I have and I got 0.7 ohms. So Bossdaddy, your meter reading is good. We are getting down to the nitty gritty now.... it is looking like the ECM have failed. But there is one or two more tests that I'd like you to make before we call it, just in case something crazy & don't make any sense have happened. With the 5p ECM connector plugged in, key turned off, 16p ECM connector unplugged, check continuity between the Green/Red wire inside the 16p ECM connector to ground. While the transmission is in neutral that wire should show no continuity. 1 Share this post Link to post Share on other sites
Bossdaddy 209 Posted June 3, 2021 I don’t have a g/r wire in the 16 p ECM harness connector. Share this post Link to post Share on other sites
Bossdaddy 209 Posted June 3, 2021 The only green wire there is g/b. Share this post Link to post Share on other sites
retro 4,048 Posted June 3, 2021 The wire is a light shade of green with red stripe. See the orange arrow that I have drawn on your photo. Share this post Link to post Share on other sites
Bossdaddy 209 Posted June 3, 2021 Meter set on 200 the red probe on g/r connector and black hooked to battery neg post reading was 17.5 Share this post Link to post Share on other sites
retro 4,048 Posted June 3, 2021 I am sorry, I made a mistake on wire color Bossdaddy. Rather than Green/Red the correct wire color is Grey/Red. So lets try that test again... With the 5p ECM connector plugged in, key turned off, 16p ECM connector unplugged, check continuity between the Grey/Red wire inside the 16p ECM connector to ground. While the transmission is in neutral that wire should show no continuity. 1 Share this post Link to post Share on other sites
Bossdaddy 209 Posted June 3, 2021 No problem, new reading is 0 on grey/red. 1 Share this post Link to post Share on other sites
retro 4,048 Posted June 3, 2021 Great! We have just two more tasks to go then we gotta make the call on the ECM. You may have done this one already, but if not find the wiring harness frame ground where it attaches to the frame with a bolt. Remove the bolt and make sure that the frame is not rusty under it. If it does not look clean shine the frame up around that ground bolt and then tighten the harness ground back down. There are 3 green wires and 1 green/white wire in that ground spade. See the pic: Share this post Link to post Share on other sites
Bossdaddy 209 Posted June 3, 2021 Where is this located? Share this post Link to post Share on other sites
retro 4,048 Posted June 3, 2021 1 minute ago, Bossdaddy said: Where is this located? I don't remember... I think that it is near the steering head, on the left side, in the front part of the frame though. Check the area where the harness connectors clip to the frame on the left side. Share this post Link to post Share on other sites
retro 4,048 Posted June 3, 2021 Here are those ground wires exiting the wiring harness near the connectors on the left side. Share this post Link to post Share on other sites