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2nd Gen Ram Tech1994-2001 Rams: This section is for TECHNICAL discussions only, that involve the 1994 through 2001 Rams. For any non-tech discussions, please direct your attention to the "General discussion/NON-tech" sub sections.
I don’t but I was about to go buy one in a little bit. Should the pcm be plugged in or unplugged when using the test light in the socket?
Leave everything unplugged. Test the brown/white wire at various points. (socket, and connector in the cowl) so your test both segments of the circuit. The test light should NOT light up.
Sorry if if missed something here but to me it would indicate that there is a problem with the pcm.
This is back in the first few pages and if you have the pcm connected and ignition on it should only prime the system then shut off. If the pump is running continuously(ignition off pcm hooked up) there is a problem in the pcm. Pcm supplies the ground for the relay, If you disconnect it and it stops there is your problem(pcm).
I assume you are trying to read voltage? Should have one lead on battery positive and the other(lead from the pcm that supplies the ground) in this pin. Don't be concerned about the 00.3 even my Fluke auto ranging meter does it. And if you are checking continuity you should be using the one with the pic of the diode(the one to the right of where it is now)
Another thing i seen don't push the test lead into relay terminals, This can stretch the terminal and then may not make the connection to the relay. Use the clip with a piece of wire into it instead.
maybe I misspoke or something ok so with pcm hooked up and ignition on the pump primes nonstop
if I turn the key off the pump turns off.
if I unhook the pcm the pump doesn’t run at all key on or off.
if I use the diode one and it goes to 0.00 does that mean full continuity? (The screen shows 1 until I touch the ends then it goes to 0.00)
Last edited by Packwood Digital; Aug 24, 2020 at 09:32 AM.
Leave everything unplugged. Test the brown/white wire at various points. (socket, and connector in the cowl) so your test both segments of the circuit. The test light should NOT light up.
ok I’ll report back with that as soon as I buy one in a little bit here. Thank you
maybe I misspoke or something ok so with pcm hooked up and ignition on the pump primes nonstop
if I turn the key off the pump turns off.
if I unhook the pcm the pump doesn’t run at all key on or off.
Yep.
The control side of the relay doesn't get power till you turn the key to on. Under normal circumstances, the pcm would ground the control circuit to run the pump for a few seconds, then turn it off, till it sees the engine turning.
On yours, however..... It ain't happenin' that way. The pump runs constantly. If unplugging it at the PCM, and everything else hooked up, prevents the pump from running........ That really points at a failed PCM. The relay will still be getting power from the ignition switch, but, the control circuit won't have a ground. The PCM can't provide it, as it is out of the loop. Since the pump DOESN'T run, that would imply that the wire for that side of the circuit is just fine.
The control side of the relay doesn't get power till you turn the key to on. Under normal circumstances, the pcm would ground the control circuit to run the pump for a few seconds, then turn it off, till it sees the engine turning.
On yours, however..... It ain't happenin' that way. The pump runs constantly. If unplugging it at the PCM, and everything else hooked up, prevents the pump from running........ That really points at a failed PCM. The relay will still be getting power from the ignition switch, but, the control circuit won't have a ground. The PCM can't provide it, as it is out of the loop. Since the pump DOESN'T run, that would imply that the wire for that side of the circuit is just fine.
so in the chance it is my PCM I’ve been shopping around the last few days for one. I’ve found used ones on eBay that match my part number or remanufactured ones from carddone
half the people say it will need to be programmed other half day it doesn’t.
i “think” I remember you saying it doesn’t need to be programmed for my year.
1.If I get one from let’s say O’Reilly (remanufactured) with possibly not the same 387AD part number wood it need to be programmed?
2. If I get one from eBay (used but 1/3rd the price) that does have the 387AD part number would that need to be reprogrammed?
The 97 trucks don't really care about vin matching, which is what the whole 'programming' thing is all about. So long as the PCM is for the same engine/trans combo that you have, PCM from 96 or 97 truck will work. 95 and older are OBDI, and are totally different, 98 and up, the way things worked changed dramatically, so those simply won't work either.
If you can get one locally for a reasonable price (junk yard?) from the correct year, and engine/trans combo, should be plug and play.
Cardone REALLY doesn't have a good rep on their remans..... but, I don't know of anyone that does..... The advantage of going to your local parts store is, if it doesn't work, you can simply bring it back.... and swap it for another one. (or get your money back....)
The 97 trucks don't really care about vin matching, which is what the whole 'programming' thing is all about. So long as the PCM is for the same engine/trans combo that you have, PCM from 96 or 97 truck will work. 95 and older are OBDI, and are totally different, 98 and up, the way things worked changed dramatically, so those simply won't work either.
If you can get one locally for a reasonable price (junk yard?) from the correct year, and engine/trans combo, should be plug and play.
Cardone REALLY doesn't have a good rep on their remans..... but, I don't know of anyone that does..... The advantage of going to your local parts store is, if it doesn't work, you can simply bring it back.... and swap it for another one. (or get your money back....)
I’ve tried all the salvage yards I can think of and only found 1 which was the 98 which I got for $20 cause I figured “what the hell I’ll try it” and it didn’t do anything.
the only option I have right now is buy one online unless you can think of somewhere who might since we are in the same state lol. I’ve tried like 10 yards the only one I haven’t is u-pull in Pontiac but they can’t tell you if they have the part only the year and make you have to drive out there and see for yourself. Which I might just do today but they only have 1 97 there and if it’s like the other U pull lot it will be licked clean to the bone.
i doubt it will work but what about a 97 Jeep with same engine and trans? (Just figured I’d ask lol)
Cardone has a bulletin about doing a voltage drop test to check an ECU would this be effective at all on mine to diagnose it?
Nah, that test is for a completely different problem.
Nope, the 98 won't work at all. Too many differences.
If any of the local parts stores have one on the shelf, its worth a shot at least.
none of them have it in stock tried O’Reilly advance autozone and Napa they are all special order SUPER lame lol
one thing I can say is I’ve learned ALOT about multimeters the last couple day’s lol
i found one at some yard in canton mi for $95 it’s from a 96 with the same engine and trans so that should work right? the part# is P56040969
the only thing still stuck in my
kind is if I test resistance from the brown white to battery ground I get that 9ohm reading.... which @Hey You says shows a short somewhere...
im afraid I’ll get another pcm and fry it because of some underlying issue I can’t seem to identify... I’m going to try it again to check my work in a few since I may have done something incorrect...
Last edited by Packwood Digital; Aug 24, 2020 at 11:50 AM.
If there actually was a true short on that wire, then the pump would run even if the PCM was unplugged. The short would provide the ground path for the relay control circuit. I am real curious why you are seeing that reading though.... Somethin' ain't quite right.......
The pump runs constantly. If unplugging it at the PCM, and everything else hooked up, prevents the pump from running........ That really points at a failed PCM. The relay will still be getting power from the ignition switch, but, the control circuit won't have a ground. The PCM can't provide it, as it is out of the loop. Since the pump DOESN'T run, that would imply that the wire for that side of the circuit is just fine.
