Yet another PCM relay question
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Yet another PCM relay question
I have a 2002 F-150 SuperCrew. Having same problems as I found in searches related to dashes coming up on the odometer. I want to change the PCM relay, but I'm not sure which one it is.
Can someone help?
One post said it's in the under-hood fuse panel. That's the one on the driver's side, correct? If so, then which one or ones need replacing?
Can anyone supply a picture for a big dummy?
Thanks
TJ
Can someone help?
One post said it's in the under-hood fuse panel. That's the one on the driver's side, correct? If so, then which one or ones need replacing?
Can anyone supply a picture for a big dummy?
Thanks
TJ
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I may have actually figured out on my own ... but questions remain - looking at the diagram in the owners manual, relay in position 304 is the Powertrain Control Module relay, and position 501 is Powertrain Control Module diode. Should both of these be changed or just one, and which one???
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What makes you think a relay will solve this problem? Is this a 7 segment display? If so there may be a way to test all 7 segments of each digits like say on power up. If all 7 segments come on momentarily on power up you know the segments are good. Then the PCM and decoder for the display are the next suspects not the relay. Maybe the PCM is commanding those segment "ON".
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Joined: Jan 2004
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From: St Louis
I may have actually figured out on my own ... but questions remain - looking at the diagram in the owners manual, relay in position 304 is the Powertrain Control Module relay, and position 501 is Powertrain Control Module diode. Should both of these be changed or just one, and which one???
You should be able to swap the PCM relay with the fuel pump relay. If the original PCM relay was bad, your cluster will now power up correctly although your fuel pump won't run.
What makes you think a relay will solve this problem? Is this a 7 segment display? If so there may be a way to test all 7 segments of each digits like say on power up. If all 7 segments come on momentarily on power up you know the segments are good. Then the PCM and decoder for the display are the next suspects not the relay. Maybe the PCM is commanding those segment "ON"
Steve
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Same symptom, but mine has eventually started each time, so far. Just got off the phone with Ford, relay is $13. Going to try that before spending big $$ on pcm or ecu.
Look back at an old post from Ranger354 (I think). He had suggested tapping on the relay to see if it will energize. As suggested elsewhere, you can also try to change the fuel pump relay for the PCM relay to see if the odometer reading returns. Of corse, the truck still won't start since you are taking the fuel pump out, but it will let you know if the relay is what you need.
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