not a single working window
 

How is this even possible? Were working on a 300cd and non of the windows work at all. We swapped in good known good switches, nothing. I directly power the window motors and they work great. The fuse is fine and I replaced it with a new one and checked continuity. Im not getting any power to the switch sockets though. My question: Is there a relay? Google searches are of no avail neither is alldata.

A lot of times the wiring in the door "accordion" get mangled and break over the years. In your case it is just a matter of tracing back the current until you find a break in the wire.

Another thing: They did work about a month ago. I doubt both sides would give out at that accordian and the rear windows dont have a door. The wiring at the switches seems like 20 or 18 gauge which seems a little small which is why Im wondering if there is a relay. On a w123 is there anything between the switches and the windows. What about between the switches and battery (besides the fuse)

I don't know but I agree a relay seems likely. Wouldn't it be one of the ice cubes? Try swapping them arround?

I think some of the silver relays in the fuse box handle windows. Not sure.

Window fuses are fuse a & b (not number fuses). The window relay is under the plastic box cover on the driver's wheel well top.

ill try swapping in a good ice cube from my 85

It's helpful when you say "the fuse" if you specify which one. There are three associated with the power windows. Do you mean fuses "a" and "b" that control front right\rear left and front left\rear right, respectively? I presume no, since you say "fuse" singular.

So you probably mean fuse 12. This provides power to the relay.

Yes, there's a relay. If Funola knows it's on the wheel well, I'll defer to his experience; but the electrical service manual says it's behind the cluster.

One more question: what's the key position when you're testing? The relay only closes in Run (position II) or start. ACC (position I) doesn't close the relay, so no power to the switches.

To isolate the door wiring, try applying power across pins 3 and 4 on the front switches; or pins 1 and 2 on the rear. Of course there are no rear doors on a CD, so the "mangled accordion" won't be a factor there.

nope. I guess at this point I will start doing continuity everywhere

When I said fuse I meant both a and b fuses. I will check no. 12 fuse however I did go through and roll all the fuses and make sure none of them were falling apart but Ill replace it with a new one just in case. I tested those relays on top of the wheel well and I will test the ice cubes behind the cluster next.

Thanks for the information on the pinout for the switches. I was wondering which ones I could apply power.

w123 power windows diagram

300D 300CD 300TD power window wiring diagram

I am going by memory from more than a year ago when I last worked on the pwr windows on my 83 300DT. If the FSM says the relay is behind the cluster, then I am clearly wrong and I apoligize.

Oops. Sorry for my mistake. I said it was in the fuse box and I had w126 in mind when I said it, not w123. Apologies for the confusion.

No slight intended. I added the reference to location behind the cluster in case it wasn't on the fender in order to help the OP with additional troubleshooting info.

I'm citing a 1982 electrical manual I haven't pulled the relay behind the cluster. And the manual isn't perfect - it has 4 pages of errata that correct other errors. My favorite is the correction for the coupe seat back locking diagram: "Seat back locking safety mechanism not shown at all."

Actual BTDT can be more helpful than the book.

Maybe it's time for a "name and locate that relay" thread/sticky. Photos and FSM/BTDT references mandatory.

Now we noticed another issue which I think is related. The car no longer supplies power to the starter relay. I dont think its the NSS. Also this morning the power windows worked momentarily so I'm beginning to think its the main ignition relay or whatever relay energizes when you switch on the ignition and then powers everything else. Is there such a relay in the dash? Possible ignition switch?

Check your battery terminals.

ok friends I got the windows working. Fuse #12 had a hairline crack. This didnt solve the starter issue. Lately the car has accidently sat withthe key in the ON (glow plugs on) position several times in the last few weeks while we work on it. Could this have damaged a relay somewhere? When I turn the key nothing happens at all at the starter. Its not the battery contacts, their tight and the car is getting electrical power and when i do attempt to crank it none of the lights dim or anything so the cars just not sending power to the starter. Im beginning to suspect that its the ignition switch itself

Clip on a Remote Starter to you Starter Solenoid and a Posative source of Voltage and see if it the Starter will crank. If it does there is a good chance it is the Neutral Safety Switch (if your car has an Automatic Trans).

I do not know if the follong info will apply to your 300CD or not:

No Cranking explanation from 240D3.OT mbworld.org.
http://www.mbworld.org/forums/diesel-forum/313982-no-crank-1984-300d.html
“First make sure the selector is in P or N. Cycle through all the gear positions and try in N.
In front of the battery is a small rectangular box. Use a jumper wire to jump from one of the large posts to the small post with the purple wire. If it cranks, you've got an issue with the neutral safety switch or the ignition switch.


Above the accelerator pedal is a 4-wire plug with a harness that runs down to under the accelerator pedal and to the transmission tunnel. Unplug it, jumper across the two purple wires in the female plug and try to start again. If it starts, you need a NSS.”

I do not know if your cars wiring is the same but I got part of this quote from another Forum concerning a no cranking problem with an 84 300D.
“First make sure the selector is in P or N. Cycle through all the gear positions and try in N.
In front of the battery is a small rectangular box. Use a jumper wire to jump from one of the large posts to the small post with the purple wire. If it cranks, you've got an issue with the neutral safety switch or the ignition switch.
Above the accelerator pedal is a 4-wire plug with a harness that runs down to under the accelerator pedal and to the transmission tunnel. Unplug it, jumper across the two purple wires in the female plug and try to start again. If it starts, you need a NSS.”

The Glow Plug Relay timer stays on for about 30 seconds and turns off. After that you would need to cycle the Key to start over with the Glow Plug. So I would say little chance of the Glow Plug Relay being damaged.

The Glow Plug Relay is not connected to the Starting Circuit until you are actually Cranking the Starter. When you do that there is a Purple Wire that either goes to a Terminal Block in front of your Battery (if you have that Terminal Block you can hook up the Remote Starter there) or is wired to the Solenoid on the Starter so that wen the Solenoid gets voltage the Glow Plut Regulator does also.

The one thing that the Glow Plug Regulator and the Starter circuit have in common all of lthe time is the Ignition Switch.

I wish I was as smart as the other people on this site. I have been working on electrical problems on cars for over 50 years and still can't do it when I don't know what year the car is. The cars here in North Carolina change the electrical systems every year. Sometimes 2 times a year.
Oh well, I guess some have it and some don't.

Paul

Well Im fairly certain it isnt the NSS since a failing nss usually gives warning HOWEVER im not seeing any reverse lights on when the key is in the on position. I will check that later.

its the nss


I jumped the wires like diesel911 stated and the car cranks.


Thanks alot guys

Did that fix you window and turn signal issues?

It does not have a designated ground point, look at the wiring diagram, you can see how the switches, switch the ground point around to cause the motor to go up or down. Look at the diagram below, your issue is most likely the ground point G102...I believe this ground point is near the shifter...

http://www.peachparts.com/shopforum/...er-windows.jpg

Nothing like diagnosing a problem that was solved three years ago.

Not that it is of any consequence, but what's the point of insisting that the ground point is not "designated?" What does that mean?

That's odd....don't ask me how I posted on a 2011 thread...

Most motor's run in only one direction and thus they have designated negative lead and a positive lead....motors that run either direction were never equipped with a specific neg and pos lead...