Alternator not working after PCM swap, HELP

[edwardzracing]

So I swapped over to a 02 PCM and did the pinout swap on my 98 Camaro. I also put in a new wiring harness as well. So now that the car is running again, my alternator doesn't work. Anybody have any ideas on what I should check to diagnose this? Really has me confused. What wires control the alternator at the PCM? Is there a fuse that may be blown somewhere? Any help would be greatly appreciated. Thanks!

Brad

[joecar]

Hi Brad, the alternator has a turn on wire which is powered by the PCM... check that you have this connected and what voltage is on it (using a DMM).

[mr.prick]

IIRC 98's have 3 wires to the alt '02 has 1.

[edwardzracing]

Hi Brad, the alternator has a turn on wire which is powered by the PCM... check that you have this connected and what voltage is on it (using a DMM).

Hey Joe, thanks for the response. Would you happen to know what wire this is on the PCM? Is this the red wire that gets deleted in the PCM swap or is there another wire that I moved from one spot on the 98 pcm to a new spot on the 02 pcm?? I just don't know what wire to check and can't find anything alternator related in any of the pin out lists that I've found online.

My luck with this car is next to zero... it hasn't moved in months. This sucks. Thanks for your guys' help.

Brad

[mr.prick]

LS1 Swap FAQs (http://ls1tech.com/forums/conversions-hybrids/312119-ls1-swap-faqs.html)

[edwardzracing]

LS1 Swap FAQs (http://ls1tech.com/forums/conversions-hybrids/312119-ls1-swap-faqs.html)

Yeah, I know about that thread... unfortunately I can't track down what pin on the 98 PCM controls the alternator... if I knew that, I could then refer to the swap info and see where that wire goes to on the later PCM's. Hopefully it's just a loose ground wire or something stupid. I love electrical issues :doh2:

[joecar]

Have a look at these circuit diagrams...


(VIN G = LS1)

[edwardzracing]

My alternator had one red wire on the plug. I'm hoping that's right. Pulled the alternator and had it tested... and it works, so I know it's a wiring issue on my end.

[edwardzracing]

Have a look at these circuit diagrams...


(VIN G = LS1)

I'm all sorts of confused. Should the wire that plugs into the alternator have 12 volts or close to that with the ignition on? And where the hell does that one wire go to?? I HATE WIRING PROBLEMS!!

[joecar]

Your 1998 red wire to alternator L terminal should be working....

red wire runs from instrument cluster pin A14, thru connector C220 pin A, and then to alternator L terminal pin B;

check that it should have approx 10V on it since the 470 ohm resistor drops battery voltage;

check fuse 9 in fuse panel next to instrument panel (on the left of, next to driver door hinge).

[edwardzracing]

Your 1998 red wire to alternator L terminal should be working....

red wire runs from instrument cluster pin A14, thru connector C220 pin A, and then to alternator L terminal pin B;

check that it should have approx 10V on it since the 470 ohm resistor drops battery voltage;

check fuse 9 in fuse panel next to instrument panel (on the left of, next to driver door hinge).

Okay, fuse 9 (Gauges) was fine. No voltage on red wire with key in the on position. Looks like I'm really screwed now. Is there another fuse somewhere in the engine bay that might have something to do with it?

When I swapped over wiring harnesses... could there be a ground wire for that red wire that's loose somewhere or not making good contact?? Wow I'm lost. This really sucks. Thanks for your help, Joe.

[edwardzracing]

I'm going to trace the wire into the interior and see if there is any voltage in there with the key on. I'm guessing connector C220 is the connector just inside the interior on the passenger side where the engine wiring harness comes in through the firewall, yes? I think I remember there being two connectors there, so hopefully one of them is the C220 connector. I'll try to track it down tomorrow and post back with the results. All the gauges are working. I'm beyond confused.

[edwardzracing]

Quick update... I have voltage in the interior after the C220 connector on pin a, so somewhere along the line out to the alternator it has a break or something 'cause there's no voltage out there. I'll see what else I can find.

[joecar]

Does fuse 9 have voltage on both ends of it...?

If the voltmeter works on your instrument cluster, then the problem will be where you said: connector C220 and/or passthru P110.

Locations:
C220: Instrument panel to engine harness, under the right side of the instrument panel, behind the knee bolster, see #8 in first doc.
P110: Right side in the dash panel, engine to the passenger compartment, see #8 in second doc.


1998 Chevrolet Camaro

(http://127.0.0.1:9001/servlets/BlobShtml?ShtmlFile=490841&pubid=55&evc=sm#oth1-490841)
http://127.0.0.1:9001/servlets/TifToGif?pic=490811

(01)C240
(02)Instrument Panel
(03)Cross Car Wiring Harness
(04)Right "A" Pillar
(05)Dash Mat
(06)C210
(07)C230
(08)C220
(09)C219

1998 Chevrolet Camaro

1998 Chevrolet Camaro

(http://127.0.0.1:9001/servlets/BlobShtml?ShtmlFile=490838&pubid=55&evc=sm#oth1-490838)
http://127.0.0.1:9001/servlets/TifToGif?pic=490808


(01)P100
(02)Forward Lamp Harness
(03)Battery
(04)C102
(05)C100
(06)C105
(07)C101
(08)P110
(09)Engine Harness

1998 Chevrolet Camaro

[edwardzracing]

Pictures aren't working for me. Voltmeter is definitely working on instrument cluster. I found the wire at C220... unhooked it and checked it... voltage. Hooked it back up, checked the wire right after the connection... voltage. There must be a break somewhere 'cause there is no voltage at all out at the alternator. That isn't going to be easy to track down either... would I be safe to run a new wire?

[joecar]

You could run a new wire for now (that's what I would do)...

and eventually one day when you have free time on your hands find/fix the break.

[edwardzracing]

You could run a new wire for now (that's what I would do)...

and eventually one day when you have free time on your hands find/fix the break.

Thanks Joe... really appreciate your help!

[edwardzracing]

Ran new wire, now have voltage at alternator clip... will get alternator put back on and hopefully report back with a charging battery :) Thanks again!

[jetblast]

looking at that schematic, your problem is somewhere between the pcm blue cconnector pin 61 to connector 220. you definitely need to verify which pin is used on that pcm to begin with, but assuming the schematic is correct, do a visual and make sure the pin is in place, at the blue connector pin 61 and also check for power there. that wire, which should be brown is only used to excite the field, so don't be concerned if it only reads 5.volts. if you have no power with the ignition sw. on, then you have to trace the wire by disconnecting the battery first, and then put a continuity mm probe on pin 61 to the gen. connector pin b. keep in mind that, that connector, according to the diagram has 2 wires both of which meet there, so you have to separate them or disconnect connector 220. if you have continuity at the brown wire circuit 25 and you are absolutely sure that there is no break between pin to pin then i would suspect the pcm. good luck!