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Has anyone ever cleaned the G107 ground on the back of the cylinder head, driver side to address driver window issues? Description indicates this is the ground for the left side DCM. If you have cleaned, what did you have to do to gain workable access to it?

I have the frequently mentioned problem with my driver window. It is in down position and wont raise. I can hear relay clicking. Everything else except the driver up control works fine.


Last fall when this problem first presented, I purchased a new dcm and regulator assy. I installed both and the situation did not change so I took them back out. After more fussing and no apparent actions that would resolve the issue, the window started functioning again. Every now and then it would not want to raise (always from fully lowered position) but if I repeatedly pressed the up side of the switch after 3-4 engagements it would work.

Couple of weeks ago got the dreaded "Pull key and wait 10 secs." Successfully installed CLB after the "service column lock" (I will post this in a seperate post). After I resolved the column lock issue, the window stopped raising again. Might be coincidence...

After several searches, this is what I have done so far"

1) Replaced battery - testing showed it had a dead cell. This is probably what triggered the service column lock message. Cleaned the ground right next to the battery.
2) Also noted that the positive terminal had loosened to the point that it was almost ready to fall off. I am suprised the car ran at all. Check your positive terminal connection as part of routine maintenance.
3) Reset the security password - code PCM P1631. It appears I threw this code somehow when I replaced battery. I threw it again after removing the negative lead to trouble shoot window issue. The reset is about a 35 minute process, so I will deal with it after I resolve the window since it appears I am going to see it every time I remove the negative lead now. This is a new development.
4) Checked the connections in the door wiring accordian harnesses per Bill Curlee's suggestions. Everything appeared fine in this area.
5) Checked voltage at the end of the connector that attaches to the window regulator motor. I am not sure I tested properly, I am going to test again today after I talk with some friends with a better electrical troubleshooting background than I.
6) I did not get a voltage reading (might not have performed correctly per above) so I went ahead and installed my new DCM. No change in condition.
7) This afternoon I am going to remove the regulator again and inspect the motor more closely. Some have indicated they were able to open up the motor and clean armatures, springs, etc.
8) Depending upon outcome I may go ahead and replace with the new regulator I have. The new "rebuilt" regulator does not work as smoothly as the original, so this will be the last step.

So - has anyone every observed that cleaning the ground G107 is of any benefit in this situation?

Can anyone think of any steps I have missed or offer a better next step than tackling the regulator motor?

 

bump

 

Since window-up is the only command not working and the relay in the DCM is closing it's probably not a ground issue. Since the other DCM didn't have an effect you can rule out a bad relay also.

Based on my experience with these regulators, the motor is likely sticking due to static friction. Raising a window requires more torque than lowering because of the extra work the motor must do to overcome gravity. The gears are packed with grease but the motor armature is dry and can start to stick if not lubricated. Remove the four screws that hold the metal motor housing onto the case and pull it off exposing the motor armature. Shoot some WD-40 on both ends of armature and at the brushes then turn it back and forth a few times by hand. That should last a couple of years until it starts sticking again.

While you've got it out check the cable to make sure there is no slack on one side. That usually indicates one of the white plastic spring guides has broken allowing the cable sheath to pull into the gear case. Symptoms for that are a popping sound and jerky ride at the start of the window travel. Currently the only remedy for a broken spring guide is a new regulator or rebuild.

Please let us know what you find.

 

I have had a similar problem with my driver door. For a while the window stopped working. So I replaced the whole regulator motor assembly. Cables were frayed a bit. Worked ok for a week or two. The started doing the same thing. You could sometimes Hit the door with the button held down, and then the window would roll up, but eventually it just stopped. I finally got the window to roll up and left it there. Now it wont go down, and over the end of fall my AC went out, so now this car sux to drive because there is no AC and the window wont roll down.

Im pretty sure now that its the driver door control module. That is were the relay click comes from when I press the window down button. I hear a click when I press, but not a click when I depress, Like when I press the up button. Im going to find a Driver DCM and replace it and see what happens.

 

It seems that the window switch activates two large blue wires that come out out the smaller connectors on the DCM. At least on my car they are large blue, but I am realizing that a lot of my wiring is changed due to aftermarket stereo, amp, alarm etc. So I do not know what color they are supposed to be.

I can get voltage on each of the blue wires that come out of the DCM when I engage the up or down switch and only one wire is energized depending upon the switch direction. The up wire was out of its connector (butt splice which is why I am suspicious these are not OEM, at least the wires (conductors).

I have traced wires and the two that come out of the DCM do not go directly to the motor connector. It appears that they travel back through the accordion loom into the cabin and return as black wires, which then go directly to the regulator motor.

I am looking for a schematic now, as it appears that the circuit is broken somewhere in the cabin. However, I do not get voltage for either up or down on these wires after they come back from cabin, and the down was functioning before and has always functioned properly. So I may be on the wrong track here due to my incomplete understanding of these circuits.

 

FF Jeff,
I feel your pain man. I had no ac and no windows one summer as well. The DCM will energize the relay, then after about 2 seconds release the relay with a second audible click if the motor is stalled. Before replacing the DCM I would suggest switching the passenger DCM in it's place. They are interchangeable for troubleshooting purposes but I think from your description a spring guide is broken and the cable has tangled on the spool. Did it groan and jerk around the last couple of times it worked?

Jazzcat,
I just assumed you already had a wiring diagram since you were talking about the ground. A manual is available for the car including all the wiring diagrams for free on the internet. Study the diagram for the window and you can tell if anything has been changed by prior owners. It' s my understanding the power comes from the DCM directly to the window motor without traveling back to the dash.

 

I have had brand new regulator assemblies, installed less than a couple of months, stick in the up position.
I have found that if you bump the window down a fraction of an inch, it unloads the drive gears, and I have not had one stick since then.
I think since the motor does not have a limit switch and just runs until it stalls, that eventually the drive gears and motor just get stuck, usually in the up position.

 

Cratecruncher

Thank you for your responses. I am familar with the grounds, both in location and somewhat in function due to a rigorous search. I pulled some great photos from another forum, although I believe the OP was simply pasting some of Bill Curlee's outstanding work (as usual) and posted to his thread.

The driver window worked extremely well when it was working. Due to the fact that I cannot get a meter reading on voltage at the motor end of the connector I do not feel that it is the motor, especially given the fact that I did get voltage for both up and down circuits when I engaged the switch, both momentary and constant in the case of the auto down mode.

I have reassembled the door. During the course of all of todays activities I drew my battery down to slightly over 8 volts so I had to abort the security password reset process.

I am almost at full power again. As soon as I get their, I am going to reset the security password and see where I am. Although unlikely, it is possible that I do not have an accurate picture on where I stopped due to the battery voltage.

I am done with this and am ready to concede to the professionals. I have spent two weekends that I did not have to spend dealing with the column lock and the inop driver window issue. The only consolation is that I probably would have been into repairs at a shop to the tune of approximately $1,600 to $2,000 to get to this point. I have a local guy that I used years ago for each of my C4's that I feel I can trust, he just is not a real bargain on the labor rate. But that's okay, he has a right to earn a living like the rest of us.

Between Corvettes I drove an M3 for almost 8 years. I have a guy for my BMW's that is an outstanding diagnostician who also offers an outstanding labor rate value. It kind of spoiled me. If he felt I could do the work he would walk me through it. If not, he would tell me and I would simply take the car to him and I trust him implicitly. I may go back to an M3 or a 645/650..however I digress.

Thanks again for your assistance.

 

Good idea. Ill try that first chance I get. No it didnt make any weird noises. And it would be a very crazy coincidence that right after replacing one regulator assembly that the replacement would then brake. But while im in there Ill check. thanks.

 

I believe I have resolved my problem, although I have to tear into it again tonight to verify.

I previously indicated that I could locate voltage coming out of the DCM for both up and down window operation. However, the wires travel back through the accordian, into the cabin and then back to the window regulator motor. When the wires return, prior to where I see them going to the regulator motor I lose the juice.

Cratecruncher indicated that he thought the wires went directly from DCM to the regulator motor, which I believe is accurate for OEM wiring. However, I have butt splices on each the up and down circuits and the wiring looks out of place. I have a strong suspicion that the wiring has been rerouted to the aftermarket alarm, i.e. valet window function, and that the problem is in my alarm circuitry. My alarm has been kind of hinky for the past several months, about the time the window problem started. I thought it was a problem with my FOB, that was independant of the window problem.

Tonight I am going to bypass the "alarm" circuit and splice directly from DCM outputs to the regulator motor.

If I am correct in my assumption, the East coast should hear my banshee cry. If not, listen for my Smith and Wesson 45 long colt.

 

Sorry FF Jeff, I wasn't sure from your description if the regulator was replaced with a brand new unit or a used one. You said the cables were frayed after you mentioned the swap so I assumed used.

Anyway, it sounds like you may have the sticky armature problem I mentioned earlier. Swapping DCM's will help you rule out the driver side DCM as the culprit but it might not fix your window. The most direct way to troubleshoot is to make sure you have power to the motor when you press the down window button using a multimeter. You can pull the connector off the motor and check it directly. When you press the button you should have battery voltage for a couple of seconds. When you press up-window button you get the same voltage but the polarity will be reversed. Also, sending power to a stalled motor will heat it up so after a few tries with the connector on the motor you can simply feel the motor cover getting warm.

If you confirm you have power to the motor I'd try lubricating the armature as mentioned in an earlier post. Once you get it working idle the engine while you raise and lower the window several times to get the Wd-40 well distributed. If you use the battery alone it will pull the battery down in short order (Those motors are hungry!).

 

Jazzcat,
Before modifying your wiring you need to study the stock power circuit so you don't hook something up wrong. Many individuals on this forum have really screwed up their wiring changing things without a diagram. C5 electronics are expensive if you get it wrong. There is a thread called "GM Service manual on DVD". Take a look and save yourself some heartache.

http://forums.corvetteforum.com/c5-t...al-on-dvd.html

 

Cratecruncher

Thanks for the response. Shortly after I sent the last information out I realized that I was not entirely sure that the relays in the DCM were the load current carrying relays.

You had previously mentioned that you thought the wire went directly from DCM to regulator motor, but I am in the process of verifying this idea.

It would seem to make sense that it is, as it would seem redundant to have the switch open a relay that in turn opened another relay to allow the load current to pass through it.

Thanks for the link.

 

Sorry for the thread jack OP.
It was frayed and didn't work the first time, so I replaced it with a new one. problem went away for about a week but then came back. Pretty sure its getting power because I can hear it click with button press. Might need to be lubed up as your stated, Ill try try the dcm (since I ordered one already) then go from there. Thanx bud.

 

Cratecruncher - thank you for your assistance. The "House" epiphany I had yesterday was accurate. I rewired my driver door regulator motor directly from the DCM and problem solved. I don't know if I have the energy or interest to pursue what the problem is in the alarm circuitry that was interrupting the current.

FF Jeff - No problem on the thread hijack. I think it is a good thing to concentrate communication on these threads. I spent many hours searching. After going through this process in excruciating detail on a couple of serious immersions, I learned a lot.

Listen to Cratecrunchers advice. The clicking you hear does not indicate the regulator motor is getting current. It simply means that the load voltage relay on the DCM is being energized. It is very simple to measure if you are getting voltage out of the DCM - it is an expensive part. Ask me how I know.

There are two places and two ways you can determine if you are getting output voltage from the DCM.

1) Multimeter - you can find a reasonably priced one at Home Depot, Pep Boys, Autozone, Kragen etc. You don't need a lot of bells and whistles.

2) Simple test light - Cheaper yet. One end is an alligator clip for ground, the other is a sharp probe. You clamp the clip to a good ground and start CAREFULLY poking around. When it lights up you have current, you just do not know what the voltage is, but for the DCM output that is not a requirement.

3) Voltage at DCM - There are two connectors on the south end of the DCM as it is installed, that have heavy gauge wire coming out of them. One is blue body connector the other is black. They are right below the larger connector with smaller gauge wires that comes from the door switch. The blue wire on the blue connector is the UP circuit. The brown wire on the black connector is the DOWN circuit. With the test probe, clamp the alligator to the door hinge, scrape a little paint off to get a good ground connection. Take the probe end and push it into the UP or DOWN wire as it exits from the DCM. Energize the door switch. It is helpful to have another set of hands here. If the probe lights up, then you have voltage out of the DCM. You should be able to observe both momentary and auto down voltage.

4) Unjless you have an aftermarket alarm with window valet, the wiring should leave the DCM and go directly to the regulator motor. Remove the speaker so you can touch the motor and remove the motor plug. Test for voltage in the same fashion as with the DCM. The requirement for this test is to ensure that current leaving the DCM actually makes its way to the motor. If you have voltage at the motor, then you have an issue in the motor. If you do not have voltage at the motor, the problem is somewhere previous.

5) If you do not have output from the DCM, pull your accordian out the the wiring between the door and the body and inspect the wiring into and out of the blue connector, and the male and female posts inside of the connector. Bill Curlee has posted some outstanding photos of the connectors and where to check. If one of these wires, connections is bad, the juice will not reach the DCM. In fact, if you are following good trouble shooting practice, this area should be checked before you dive into taking the door apart as it is first in line and doesn't require major dissassembly to observe.

It is recommended that you disconnect the negative terminal of the battery while you are disconnecting stuff. After a point, I was unplugging and replugging stuff so often that I stopped doing this and just made sure that the key was off and out of the switch any time I unplugged something specific to the window controls.

Resist the urge to simply start throwing new parts into it. That can get expensive fast- ask me how I know. The ridiculous thing is I know better, but I was looking for a quick fix and some of the threads I found in search seemed to indicate that "THIS IS THE FIX". If I would have utilized proper trouble shooting procedure when I started, I would have saved myself a lot of heartache and money.

I hope this is helpful to you.

Cratecruncher - thanks again. If you see any errors I have made above, please correct them as I sense you are smarter about this stuff than I am.

 

Well my problem was fixed. I replaced the DCM and works like a charm again.