K-Spaz

I'm in the final stages of swapping a A4 to M6 in my 98. Go to turn the key and nothing, clutch switch wiring is required (I am assuming anyway).

I've searched for quite a while and found a few writeups about what I'm looking for, but there is considerable ambiguity in the posts. Some on this forum, some on others, nothing really shows what I need to do. Some describe wiring changes, but unless I'm just really dense, they don't say what to do with it. Just what wires to look for.

I've got the tunnel all reassembled so I hope I don't have to get back in there. There is a lot of mention to C146, but I have no idea where to find that or what to do with it when I do.

I'd like to get the reverse lockout, clutch switch and cruise to all work correctly. To begin with though, I'd like to start the car.

Any help is appreciated.

(edit) Post 35 has a fair amount of updated info to help with understanding the rest of the things mentioned in the thread.

Greg_E

PM sent.

K-Spaz

Ok, I think I'm getting warm now. At least on the clutch switch wiring.

I've got the old motor/trans/rear sitting here with the old A4 harness on it. There were 2 20 pin round connectors on there, and then 3 other connectors that are oblong, those are less pins, I didn't count. (edit) they are 10 pin rectangular connections.

When I did the swap using the M6 harness on the trans, that had only 4 plugs instead of 5 for the Auto. One of those that was missing was a 20 pin. The one that plugs in, both have blue insides, has the yellow and purple wires, but... there are only 6 wires in that connector on the auto harness and 10 wires in the manual harness. The yellow and purple wires in there side by side. I'd like to think those are the ones that need to go to the clutch switch. So if I jump those, the car should crank. (I am guessing here from what I've read). I'm going to try to test that now.

Thanks

(more edits)
Normally I'd just post again but I had some misinformation above so I cured that.

I have a service manual here. So, if I knew how to follow what the schematics said I'd probably be ok. But, getting from one to the next and doing a compare, then attempting to find where those items are on the car, I have no idea where people find that and identify connections.

I wanted to just jump those pins on what I thought was the unused connector, but that connector is in use so I'd have to cut the wires or pierce them to test it. :| Not thrilled about cutting/exposing wires to test, at least without a better confidence of success.

thumpur

Heres an attachment to some information I found to be useful. But this is for 2001+ I know the wiring is a little different. I hope it helps



Also here is a link I found useful when I did my swap

https://www.corvetteforum.com/forums...uccessful.html

K-Spaz

Thanks, very handy PDF there. I swear there's none of this in my 98 service manual. I know there is none of the manual transmission stuff in there.

I had also found that thread linked above, but in there I read this:
and thought? Huh? He's not done it yet? Well, mine clearly doesn't start so I am skeptical of the wiring working unless he means if you bought the entire under dash harness, which involves one hell of a lot more work still. That's a lot of disassembly to go through, not to mention I don't have that harness. I could get one in a few weeks, but not sure I want to deal with that.

thumpur

Found the picture I was looking for yesterday

K-Spaz

I have that image, what I don't have is anything that shows what those wires go to when you've got a Manual. Those wires now go into the trans harness, (I am not even positive I've got the correct wires). IF I do, then those two go to gawd only knows where because I cannot find in the Service manual where there are any schematics that show the manual trans. Clearly it does not go to the pedal because I don't have wiring going to the pedal. The trans harness I have goes to the trans.

I have the battery charging now due to me thinking that letting the OBD2 connector for HP Tuners on overnight may have run my batter down and is giving me a few new codes. Right now I get 4 codes, PCM P0107C, P0705HC and P1518HC, then TCS C1276HC. The ROM 0107 might just be something that will go away over time from what I read. The P1518 might just be low voltage. The other two are clearly trans related and I'm not worried about those yet.

Other than that I get a SDM no comms message that I may be able to ignore too. Might also be voltage. I really don't know. I don't recall ever having that come up in the past but it's been so long since I looked for codes I really can't say for sure.

I was willing to cut and reroute the purple and yellow wires but that means cutting the harness. I could just jump them but that also means cutting the harness. I'd prefer not to do that without seeing a schematic for a manual that tells me what they are back at the trans. They DO go to the trans somewhere now in the manual harness. I just have no documentation to tell me where.

K-Spaz

The car was perfect before I began so I am inclined to think the PCM and TAC module are just fine, just not talking real well.

K-Spaz

Battery is still charging at 4A continuous for about 5 hours now and still taking a charge. Not sure what's up there. I disconnected the battery and did a check with a meter and the car was pulling all of 30ma. So, certainly not some huge draw. By morning I hope to see a battery that is topped off and maybe my two serious codes will go away.

In the meantime, I tracked down the theft deterrent relay (with positively no help from the service manual) and jumped across the purple and red wires. Funny enough, according to the manual, there is no red wire, but that's ok, I'm pretty much getting used to it being totally bogus at this point.
Jumped C1 to A2 and pow, the starter engages. So at least that part is functioning and I know the starter is right. Now as soon as my connectors get here for the clutch pedal switches I can start messing with that and see if I can get this thing to go vroom.

thumpur

Check out post #14
http://www.digitalcorvettes.com/foru...2821?_k=7wvsom

I don't think the problem is in your clutch safety switch because jumping the red and purple wires should start the vehicle. (Ensure that the key is in the ON position and that the vehicle is in NEUTRAL)

Greg_E

Just to clarify for the OP:
Jumping the red wire 542 at C1 of the TDR relay and the purple wire 6 at A2 of the TDR bypasses the TDR relay and clutch position switch entirely. The purple wire at A2 is not the same purple wire going to the clutch position switch. It is on the contact ( high current) side of the relay , as is the red wire. The yellow wire from the clutch position switch goes to the coil side (control)of the relay at C2 and the YEL/BLK wire at A1 goes from the coil to the BCM.

I think we know what needs to be done with the clutch position switch and the start circuit. What we aren't clear on is the manual transmission controls. Looking at that schematic you will see pink wire 339 also going to the clutch pedal position switch and terminating at the PCM. Those terminals are also labeled A and B like the start circuit. Either those terminals are mislabeled and the clutch position switch is a 4 wire two pole switch or the switch is mislabeled. Can someone with a 97 or 98 manual trans. confirm whether the switch is 2 or 4 wire?
Also we don't know what the PCM is doing with that signal. Will that also inhibit the start circuit? On the 99 schematic wire 339 goes through the cruise control release switch. Very different than the 98.
Once that is sorted out we can work on the reverse lockout solenoid and skip shift solenoid.

K-Spaz

Just to clarify, this job isn't a rush. I'm sorta working on it at in between times at work, which these last few days has not given me much time.

Greg E has it correct above in that, it's not so much not being able to get it to work as it is wanting to know what I'm cutting before I cut. I'd really prefer to get the wiring right as the service manual would instruct, but my SM has a whole host of omissions, not to mention wire colors wrong. It took me about 5 minutes of looking at the TDR connector to figure out what wire was what due to the colors not matching and signals not being what I expected. That sort of thing makes following the schematics a little tougher.

Got a customer just walked in so gtg...

Greg_E

I was scrolling through the list of DTCs looking for something to confirm that there are two clutch position switches and when I looked at DTC P0704 it confirmed that on the 98 there are two switches, one for the start circuit and one to provide a clutch pedal position status to the PCM. Never having seen the clutch position switch on a 98 I don't know if there are two completely separate switches or two switches contained in a single package. It really doesn't matter but there are are two circuits that need to be connected.

I also Looked at the DTC P0571 Cruise Control Brake Switch Circuit and that looks like it has all the information needed for the cruise control. It doesn't look like you would need to change anything unless you are going to install the the brake pedal for the manual transmission.

DTC's P0801, P0802, and P0804 address the Reverse Inhibit Solenoid, Skip Shift Solenoid and 1 to 4 Indicator Lamp. I'm sure you're going to disable the skip shift solenoid either through software or one of those plug in devices to trick the PCM to sense that the solenoid is plugged in. For the skip shift eliminator and the reverse inhibit solenoid to work you will need to verify that those wires run all the way back to the to the proper pins on the PCM connector. The PCM harness for the AT and MT have different part numbers. Also this is where you you will need to find a place to tap into wire 339 for power.
That should keep you busy for a while!!!!

K-Spaz

Ok, got the connectors and my spark plugs in the mail. Bout time.

What I got was a few plugs and wiring removed from a manual car under dash harness. I am thinking this should complete the plugs I need. Thanks to Brian at VetteVillains and Silas at WreckedVettes for the quick turnaround on these. 10 days faster than Autozone can ship spark plugs. :p

Looking from left to right Silas sent me 4 connectors (and enough wire to actually make the connections.)

1 - Grey plug, 3 wires, 2 contacts. Orange, white and lt blue (wh & lt bl are joined to one contact). This goes at the back of the brake pedal and matches what I've got from the automatic.

2 - Black plug 2 wires, 2 contacts. Yellow and Purple, this is the one we've been talking about. Goes to the switch at the rear of the clutch pedal for starter interrupt.

3 - Black plug, 4 wires, 4 contacts. Pink, grey, pink, purple. This replicates a plug that I've already got at the front of the brake pedal but on this new arrangement, the leftmost pink is also joined to the pink on the 4th plug show in the photo, obviously something to do with the cruise disengage.

There's a total of 3 plugs at the front of the brake pedal (travel), pic shown below, which I assume are all normally closed switches which open when pushing on the brake. In my pic, connectors #1 and 3 are connected there. The third connector looks similar to #3 with 4 connections but 2 wires. That I don't have a replacement to, and I have no reason to believe I need one. Those wire colors are Orange w/white and Green w/white.

4 - Black plug, 2 wires, 2 contacts. Pink and Grey wires. The pink piggybacks off the leftmost pink wire in connector 3 in the photo. That grey wire does not piggyback in. I have not looked at the book to see what this is but I suspect it's a cruise disengage. This looks like it was wired partially by GM, the one connection doesn't look like a backyard mechanic job. But there's also the twisted up part and the tape, none of which is particularly confidence inspiring.

My last pic shows the clutch starter interrupt switch with no wires attached directly below the clutch pedal return spring.

K-Spaz

I'm glad I didn't cut into that 20 pin PCM connector to wire in the clutch switch because the 20 pin connector I have, has the purple and yellow wires but they go to the speed sensor on the top of the diff. Certainly not what I wanted to mess with.

Greg_E

The 2 pin w/purple & yel wires plug into the clutch position switch for the start circuit. See if there is another socket on the clutch position switch assembly that the 2 pin connector with the pink & gray wires will plug into. Those are the clutch position status signal wiring that goes to the PCM. Refer to the DTC P0704 pdf I sent you. (Edit: I checked my C5 Parts CD and the clutch position switch is the same for 1997-2000. I checked my 1999 MT C5 and there is no socket to plug the connector with pink and gray wires into that switch, and it would be the same for the 98. I have no clue where that clutch position status switch for the PCM signal is located. Can anyone help us with that?
That pink wire is wire #339 and it has a jumper to both of the pink wires in the 4 pin connector with the two pink wires, purple wire and gray wire. You may not see a jumper between pin B and D on the 4 pin connector but I think if you Ohm them out you will find they are the same wire. Because those switches are critical to safe operation of the vehicle, Gm may have run two discrete wires from minifuse 19 to each switch. If one doesn't work due to a broken wire, the other will. Just a guess on my part. You would need to prove it out.
Wire 339 is minifuse 19 power distribution to the clutch position status sw, cruise control brake switch, extended travel brake switch and other things. Refer to DTC P0571 pdf. pins B and D on the brake switches. When you find the pink wires (also circuit 339) for the transmission solenoids , you can splice them all together and bring them back to minifuse 19. If you can find a circuit 339 wire that is already connected to minifuse 19 under the dash you can splice into that. Or add the jumper to the existing brake switch connector and connect it to the clutch position status switch and the two solenoids. You know that the wire in that connector goes back to minifuse 19 for sure.

Greg_E

I haven't found the VSS schematic for the MT yet but if you look at the Cell 39 Vehicle Speed Sensor for the AT that I sent, you will see that those wires are also purple and yellow. The good thing is that now we know that the inline connector that plugs into the PCM harness is C142.
As you work with the other schematics you will see C142 shown for other wires going to the MT.

I found the MT VSS circuit and sent it. They did not label the connector in that drawing. The wires go to the same pins on the PCM connector. No changes needed for that.

Greg_E

Thanks for the info
Being mounted under the dash would make sense, as the pink wire (circuit 339) is a jumper from the four wire connector for one of the brake pedal switches. (See post 14)
I was confused because in the 98 manual both switches are label as Clutch Pedal Position Switch.
I was able to use a flashlight and inspection mirror to view the switch and it is mounted under the dash.

The 98 manual on DVD that I have does not list a DTC P0833. It was probably added when they upgraded the PCM later on.

The clutch pedal position switch on the 98 Manual Transmission Control Schematic is shown as a normally open switch which I suspect it is. It is a normally open switch held closed by the pressure of the clutch pedal return spring on it. Even the description in the 2004 manual that 8VETTE7 posted is technically incorrect. The switch itself is a normally open switch. In normal operation it is held closed.

Just a reminder to anyone using this thread to do an A4 to M6 swap on a 1998. The pages that 8VETTE7 posted are from his 2004 manual. They are just to illustrate a point. They can't be used for the 1998. The PCMs are different.

Greg_E

Here is a picture of the Clutch Pedal Position Switch for the PCM signal AKA Cruise Control Release Switch.

On the 1998 MT Control Schematic it is called out as the Clutch Pedal Position Switch. The 1998 Cell 30: Starting Circuit
Switch is also called out as the Clutch Pedal Position Switch.

If you go to the 1998 Master Electrical Component List this is what it says.
: Mounted on the bracket in front of the brake pedal. That might be true for the AT but not for the MT.

If you go to the 1998 Engine Controls Connector End Views, it says the gray wire is the clutch switch signal.

Glad we got that all straight.

If you go to the Cell 35: Stop Lamp Switch And Miscellaneous Solenoid Schematic you will see that the pink wires Circuit 339 are all tied at splice S213. Cruise Control Release Switch, Extended Travel Brake Switch and Cruise Control Brake Switch. The trans solenoids are also spliced to the same wire 339 but it may be a different splice location if you look at the way it is drawn.

Greg_E

Phil mentioned he couldn't find the TDR Location in his hard copy manual and I didn't see it in the DVD version that I have. He has since located that relay, but for future reference I will post this location diagram for a 2002. Should be the same for all. You may not need to unplug the BCM but you will need to move it out of the way.