Major Electrical gremlin
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Elder User
Joined: Aug 2015
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I do get other relays clicking. There not that loud, but I think the pcm relay goes, the two bottom ones in the other row. I'd have to use my test relay in each one to know for sure, but others do click. Not a lot of clicking, just once.
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Elder User
Joined: Aug 2015
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I will check the idm relay again after dinner here. But I tested it several times and I have battery power to pin 30, as it should all the time key on. 85/86 are both dead. One of them should have the voltage your talking about. Pin 87 should only have power if 85/86 energize the coil and closes. Which it cant do at the moment. In the schematic 27-3 it shows that relay having power to all 3 terminal 85/86/30, 87 energized. Which confuses me to hell.
Logistics Pro
Joined: Aug 2009
Posts: 3,609
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From: Arizona
Well yes terminal 30 has power and is waiting for the relay to close so it can deliver it to the IDM, but if terminal 86 does not get battery voltage it will never close. So if you have battery voltage at fuse 22 but not at IDM relay terminal 86 than something is open in between the two. Your suspicions about the fuse box may be right. If it were me I'd be tempted to rig up a jumper from the top of fuse 22 to terminal 86 of the IDM relay to see if it closes. By coming off the top of the fuse the jumper will be protected and if there is a short the fuse will blow.
But first check for battery voltage at the IDM relay #86 to ground.
If we can figure out why the IDM relay is not closing we will have it. (but you already knew that)
But first check for battery voltage at the IDM relay #86 to ground.
If we can figure out why the IDM relay is not closing we will have it. (but you already knew that)
It's a Van Gogh
Joined: Feb 2010
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From: Elk Grove, CA
Whatever you're doing to the PCM to make one corner get hot, it ain't good.
I've read several times any wire wrapped in red tape aka IDM wires should not be probed. Breaking the insulation is starting the clock on corrosion and eventual failure. I'd hit any punctures with liquid electrical tape, not RTV.
IIRC you mentioned a tan box under the steering column with a bunch of alarm splices. That sounds like the ignition switch, which sounds like the most likely suspect to me. Mine was fritzing and resulted in very brief power loss to the PCM, so I can imagine a permanent fritz would be like your symptom. I'd replace that and leave off the alarm stuff. Pic of the part with part number below.
I've read several times any wire wrapped in red tape aka IDM wires should not be probed. Breaking the insulation is starting the clock on corrosion and eventual failure. I'd hit any punctures with liquid electrical tape, not RTV.
IIRC you mentioned a tan box under the steering column with a bunch of alarm splices. That sounds like the ignition switch, which sounds like the most likely suspect to me. Mine was fritzing and resulted in very brief power loss to the PCM, so I can imagine a permanent fritz would be like your symptom. I'd replace that and leave off the alarm stuff. Pic of the part with part number below.
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Elder User
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Ok. The idm relay has power, 11 volts to terminals 30 and 86 with the key on. Only 30 with the key off. I must have had the fuse out the first time I checked. But I did it 3 times and the info is right this time.
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Elder User
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The pcm does get hot. Just like a lap top or phone. But it could be getting localized like that because of my issue. I do suspect that ingnition switch, although wiggling and messing with the wires won't bring it back. Usually you can get it to do something indicating a broken wire. The splices were done good and soldered and are for the key on power to the alarm. I don't think its the wires, BUT my key is real sloppy and I can get the buzzers to turn on by using another key in there and wiggling. Its pretty loose, as is the shifter. I have to lift the shifter a bit to unlock the key. So I suspect if its my issue then its in the key part itself, not that white box with the wires. Unless that box is whats loose and contacting if I wiggle the key.
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Elder User
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If the key were the issue, would the whole fuse box not be dead? Ive pretty much narrowed it down to one relay not tripping shutting down all my dead stuff. Just cant figure out why. Relay has power to 86, power at 30. Why is it not tripping. No one has mentioned the diode I saw on drawing 27-3. Power comes out of the pcm relay and into the pcm power diode, then to the pcm. I also suspect that diode may be gone stopping that power or changing it some how. The pcm may use that power to energize pin 85 on the idm relay thus tripping it. What is a diode, and what is its function here. It appears to be inside the fuse box, and none serviceable.
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Logistics Pro
Joined: Aug 2009
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From: Arizona
OK so you have battery voltage at the IDM pin 86 but it still won't close, and you tried a different known good one, so it is not getting the other half of the circuit it needs to close.
I finally figured out how to get around the write protection on my Ford CD and I made a pdf of the pinpoint tests for the PCM,IDM and harnesses. If you PM me with your email address I'll send it over. Some of the tests use a breakout box but you can get around that by just going pin to pin on the components themselves.
I finally figured out how to get around the write protection on my Ford CD and I made a pdf of the pinpoint tests for the PCM,IDM and harnesses. If you PM me with your email address I'll send it over. Some of the tests use a breakout box but you can get around that by just going pin to pin on the components themselves.
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Elder User
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Don't know how to pm, but put my email on your profile page with some other ones from other people. I didn't think you could test the idm and pcm without it communicating. I look forward to confirming if mine are good or not. I can't stop thinking about that diode.
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Elder User
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Ok got it. Getting started now. It will take some time, but I'm on it. I will try to have it done to post results when I get home from work tomorrow. Unless I can get it done tonight, but its late here already. Ill try. Don't give up on me, I will be back. Diode???Hmmm
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Elder User
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So just going over these tests. The schematics in this test are much more accurate. My set of drawings is for the econoline, so pin 80 is not my signal, and I've been testing the wrong pins on the pcm. Probably the idm too. Good I found that out. Its actually pin 71 for the f series. Lol. At least Im getting some were. Thanks big 56. The drawings also show the wire colors correctly. A little easier to see were I'm losing power. Now to confirm it with these test.