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Discussion Starter · #1 ·
All windows quit working No power to master power window switch. 40 amp fuse and 15 amp fuse have power. I get 12 volts from one spot on the relay. Can someone please tell me the wiring circuit. It starts with battery then 40 amp curuit breaker then what? Where does the body control module fit into the circuit? And has anyone ever heard of just the power window part of the BCM giving out? Why don't I have power to the master window switch?
 

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You could pull the relay and jump pin 30 to 87 in the junction block and see if that works. It could be a bad relay. If you tested for power across the pin 10 and pin 13 then it could also be the ground. G301 needs cleaning or a broken wire.
 

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Discussion Starter · #4 ·
I put a new relay in and still no power to the center consul master window switch. I have started tracing the pk/yl wire back from the center consul master window switch to the relay. I can't figure out where the wire comes out from the relay. Any tricks to locating the pk/yl wire coming from the relay?
 

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It's pin 40 of the C2 connector. Did you try jumping 30 to 87? That bypasses the control circuit and would eliminate it as the problem. When you tested for power at the console did you test from pin 10 of the connector to a nearby ground like a seat belt bolt or to it's ground wire? Do you have power at pin 30 of the relay? The pin numbers should be marked on the relay.
 

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Discussion Starter · #9 ·
It's pin 40 of the C2 connector. Did you try jumping 30 to 87? That bypasses the control circuit and would eliminate it as the problem. When you tested for power at the console did you test from pin 10 of the connector to a nearby ground like a seat belt bolt or to it's ground wire? Do you have power at pin 30 of the relay? The pin numbers should be marked on the relay.
I bought a new relay so I ruled out the relay BUT when I jumped pin 30 to pin 87 I got power to pin 10 on the window master switch and the windows worked.
While 87 and 30 were jumped I tested pin 10 to 13 to check the ground and it is good (12 volts)
So the control ciruit is the problem since we bypassed it and the windows worked. What exactly does the control circuit mean and how do I fix it? And could I have bought a bum relay (although I have tested it with a spare relay also and windows didn't work?
Thanks
 

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Short Version:

  1. Check fuse 1.
  2. If fuse 1 is good, check for power at fuse 1 feed in fuse block.
  3. If no power there, repair feed wire.
  4. If power there, check continuity from pin 85 of the relay socket to ground.
  5. If no continuity there, repair ground wire.
  6. If continuity there, check continuity between pin 85 and 86 of the relay itself.
  7. If no continuity there, replace relay.

Long Version:
The relay has two circuits in it. The purpose of the relay in this case is to allow you to control a high amp circuit with a low amp circuit. It accomplishes this by using a coil on the low amp circuit of the relay. When the coil is energized (positive to one side and negative to the other) in the relay, it creates a magnetic field which pulls the load circuit switch (which is connected to pin 30 on the "hinge" side) from pin 87a to pin 87. So that completes the load circuit as pin 30 is now connected directly to pin 87 which feeds your master window controls pin 10 through the yellow/pink wire. The control circuit coil is connected to pins 85 and 86.

So if you look at the diagram posted earlier of the power window relay, you can see where the load circuit pin 30 is connected to 12V. The load circuit when the control circuit isn't energized (at rest), is connected to pin 87a. Nothing is connected outside the relay to pin 87a so the load circuit stops there. So when you jump pin 30 to 87 directly, you are bypassing the control circuit needing to be energized.

So the control circuit in the relay is pin 86 and pin 85. The diagram shows the internal coil in the relay. One side (either side) must go to positive and the other side goes to negative. Barring a bad relay that isn't moving the internal load switch when the control circuit is energized, the problem lies in the positive (pin 86 in this case) or the negative (pin 85) connection. Test for power at pin 86 of the relay socket with the negative probe directly to ground (engine, chassis) with the key in the run position. If you don't have power at pin 86 then your problem lies between pin 86 and the battery. Pin 86 is fed power from fuse 1 (15A). Test if fuse 1 is good. Make sure you test it with your meter (continuity). They can sometimes look good to the eye but still be blown.

If you do have power at pin 86, then your problem lies in the pin 85 ground side. Check continuity between pin 85 in the socket and ground (again engine, chassis). If no continuity, then your ground connection was lost. Unlikely as a lot of accessories use this same ground.

You can also test the relay control circuit with your meter by checking continuity between pins 86 and 85 of the relay itself. They should have continuity across the coil.

Okay, maybe too much information but I hope it's helpful. It's good to have a basic understanding of how a relay works when troubleshooting.
 

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Discussion Starter · #11 ·
I tested pin 86 with the neg probe ground to the vehicle and I have 11.6 v which is what my battery tested. I jumped pin 85 directly to ground, stuck positive probe to the jump wire and grounded the black probe to a separate ground and had 11.6 v. I also put pos. probe to pin 86 and neg probe to pin 85 and got 11.6 v. I realized that the relay that came with the used jeep did not have pin 87a so I went out and bought a new relay with pin 87a thinking for sure this was the problem but the windows still don't work with the new relay. Now what? lol
Thanks for all your help.
 

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Discussion Starter · #13 ·
I had an idea. I went out and hooked a small piece of stainless solid wire to the relay pin 85 and ground it to the vehicle and plugged the relay in and my windows work. So shouldn't that mean it is the ground on pin 85 that is bad? How do I find where the ground wire is?
 

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Yes, that's what it means. So now I'm thinking, since you had power when you tested the ground with the meter, that the female pin in the junction block itself is dirty or the pins are spread too far apart to make a good contact with the relay pin 85. You could spray it with some contact cleaner and see if you can bend the female pin more closed.
 

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Discussion Starter · #15 ·
This is mind boggling. The only way the windows will work is if I hook pin 85 up to a small solid wire and the other end up to a ground and then plug the relay in. But when I do this the windows go up and down without the ignition turned on. With the ignition switch OFF I have power in the sockets of pin 30 and pin 86. Is there supposed to be power to both of these pins with the ignition switch off? I tried cleaning the contact on pin 85 and closing it more and it still doesn't work. Does the body control module have anything to do with this relay?
 

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You can always have power to pin 30 if it is not switched. Usually when a relay is used the control circuit handles the switching. You can always have power to pin 86 if the negative side of the control circuit is switched (needs ignition on for power). That obviously is the case here. So now we need to figure out where the negative ground wire for the control circuit is switched. Could be in the BCM. I'll see what I can find in the FSM.

Edit: The attached shows that pin 85 is attached to the Accessory Delay Relay Control. I believe that allows you to put up the windows and close the sunroof after the vehicle is shut off, but only for a set amount of time before it loses power. That is in the BCM, pin 7. You could try cleaning that. Do you have a power sunroof? You may have been testing for power within that time delay. It also shows that pins 30 and 86 always have power.
 

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The ground is obviously switched. Otherwise the power windows would always have power since pins 86 and 30 do. I can't imagine it being switched within the junction block itself. So I'm guessing the BCM controls it although it's not listed as one of the functions of the BCM in the FSM. :dunno: If it was a ground pin issue with the BCM, I would expect a lot of other problems besides just the power windows as many functions share the same ground. That's why I suspected pin 7 in the BCM as that is where the ground feed for the windows is fed in.

Maybe a broken ground splice within the junction block? You could test continuity from pin 85 in the junction block to pin 7 in the BCM connector for that. If that has continuity, then most likely a problem with the BCM or PCI. If no continuity then likely a problem with the junction block itself. I really don't know at this point. If all else fails, you can wire a new ground from pin 85 through a relay and have it work only with the key on.

To perform a continuity test, set you meter to ohms. Touch your two probes together and it should show zero resistance. When the probes are not touching, it should show OL for open line or a 1 depending on your meter. So put one probe on pin 86 and the other on pin 7 of the BCM connector. If it shows resistance instead of OL or 1, the junction block is okay.
 

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The FSM states that if you are replacing the BCM then you need to program the new one. However, I don't see anything related to just removing it except that the hard wired input and outputs can be tested normally. Of course you should disconnect the negative battery cable whenever doing electrical work. I would expect it to just reboot when you reconnect the battery but you may interpret it differently.
 

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