HM20 Troubleshooting

[KPierson]

All HM20 modules shipped beginning 1/1/2010 (and some shipped before) have a built in diagnostic LED to help troubleshoot installation issues.

The LED is internal to the unit, but can be seen by looking inside the case through the wire harness cut out. They are fairly bright LEDs and should be easy to see without taking the case apart.

The first step to using the LED is to hook everything up (don't forget to use a volt meter to verify EVERY connection) and then simply hit the "LOCK" button on your remote. When the doors lock the LED should flash quickly. Please note - if the doors do not lock the LED won't flash so make sure the door actually locks when you hit the "LOCK" button.

If the LED doesn't flash verify with a volt meter that there is ~12vdc between the modules black and red wire at all times. Also, verify that there is NOT ~12vdc between the modules black and yellow wires at any time expect when the ignition system is turned on (it is OK for the line to stay high with retained accessory power - the system that keeps the radio on and windows working until you open the door in many new cars). If you are unsure at all about the yellow wire simply disconnect it - it is only a safety input and can be disconnected for testing purposes.

If the LED flashes when the door locks as soon as the LED goes out press the "LOCK" button again - this should cause the LED to come on and stay on for ~10 seconds. For this 10 second period the green wire of the module should be outputting a ground signal telling the windows to raise. If at any time the module starts flashing count the flashes. If the LED flashes twice that means that voltage was detected on the yellow ignition input wire and the window output was shut off for safety reasons. If the LED flashes three times then that means that voltage was detected on the blue lock actuator wire and the windows were shut off remotely. If either of these fault conditions occur unexpectly (ie you didn't turn the ignition on or press the "LOCK" button again) check the signal on the appropriate wire.

If everything seems to be working but the windows still are not going up with the module then verify that the green wire of the module is connected to the correct wire inside the car.

With the feedback the LED provides it should be much easier to troubleshoot the installation of the HM20 module. The majority of issues reported with this module are due to incorrect wiring inside the car so make sure you double check all wires before making any connections.

[integ2be]

Hi there,

I just tried installing my HM20 into my 2006 Acura TSX but I am having a little bit of a problem. The window rolls up after hitting the lock button "ONCE" instead of twice. AND it does not always work.

So for example, if I roll the windows down by pressing it on the remote then locking it right after, it will go back up. If I were do it after a period of time, lets say after a drive, it does not work. I tried pressing it twice with a second "PAUSE" in between as well, nothing.

Please help. I have followed the instructions on the forums and on the paper work.

The only wire that I didn't seem to find was
"Lock Actuator (BLUE) to the Acura Yellow/Black" ... I did not see this yellow black. I instead used the yellow brown.

I did see a black with a yellow stripe, but that was on the harness for the power mirrors. Is this the cable that I should be using instead?

Please help when you have a chance.

Thanks in advace.

[KPierson]

Hi there,

I just tried installing my HM20 into my 2006 Acura TSX but I am having a little bit of a problem. The window rolls up after hitting the lock button "ONCE" instead of twice. AND it does not always work.

So for example, if I roll the windows down by pressing it on the remote then locking it right after, it will go back up. If I were do it after a period of time, lets say after a drive, it does not work. I tried pressing it twice with a second "PAUSE" in between as well, nothing.

Please help. I have followed the instructions on the forums and on the paper work.

The only wire that I didn't seem to find was
"Lock Actuator (BLUE) to the Acura Yellow/Black" ... I did not see this yellow black. I instead used the yellow brown.

I did see a black with a yellow stripe, but that was on the harness for the power mirrors. Is this the cable that I should be using instead?

Please help when you have a chance.

Thanks in advace.

What did the yellow/brown wire measure when you tested it with a volt meter? It is absolutely critical that the correct wires be identified and used, otherwise the module won't work. Also, you should be able to use the diagnostic LED to verify if you have the correct lock wire by following the instructions above.

[integ2be]

I will have to double check when I have a chance, but I am pretty sure that I got all the correct readings ... could not do it today since it is Easter weekend. I will try sometime this week, if not then for sure next weekend. Thank you for your quick response.

[integ2be]

ok...

so I finally had a chance to try it again but with no luck ... The Module does not flash. It is either on or off. It rolled up a couple of times, then it didn't work anymore.

Black is black, no voltage (ground)
Red is constant 12 volts with the black.
Yellow only has power (12 volts) when the key is turned, otherwise, no voltage.


The green reads 5 volts when the lock cylinder is in the lock position. It did it a few times, but sometimes it would stay at 5 volts and not drop to 0 when in the lock position. I cannot find one that always does ...
and ...
The blue reads 12 volts for a few seconds then drops to 0 (no voltage) after a few seconds when the lock button is pressed.

I am getting annoyed with this install, please help.

[KPierson]

Everything sounds close to what it needs to be. Are you sure the lock actuator wire (KPtech blue) stays at 12vdc for a "couple seconds"? It should stay at 12vdc for ~0.3 seconds. This means when you issue the first "LOCK" command the LED should flash quickly, not stay on as the LED stays lit for the entire period that the LOCK actuator is at 12vdc.

If it is staying at 12vdc for an extended period of time you will need to adjust the timing of the "LOCK" "LOCK" commands. You must wait for the signal to drop back to 0vdc before issuing a 2nd "LOCK" command.

The fact that it has raised the windows a time or two backs up my belief that many of the wires are correct. The timing is the thing I am most concerned about right now.