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Last year, I replaced a pop up headlight module that was ticking and show other sight of failing. I replaced the defective module with a used one. I kept the failing module and opened it up to see what was going on inside (See the photos). There seems to be no water intrusion, burned, or corroded contacts. The components inside of the box are clean as far as I can tell. I am guessing the ticking was the switches inside the relay that is soldered to the board.
Is it possible to de-solder and re-solder another relay onto the board? Has any one done this? And did it work.
I bet it is NOT the relay. Carefully inspect all the solder joints, on the entire board (especially the connector pins, and the 3 pins of Q1 and Q2), and look for hairline cracks. Resolder those and I bet the module is good-as-new.
Last edited by ersatz928; Feb 8, 2017 at 01:58 PM.
I bet it is NOT the relay. Carefully inspect all the solder joints, on the entire board (especially the connector pins, and the 3 pins of Q1 and Q2), and look for hairline cracks. Resolder those and I bet the module is good-as-new.
I've spent the last hour inspecting the boards solder points under high magnification. I was unable to see any issues with the solder points as described. I payed particular attention to Q1 and Q2 as directed, but no cracks or lose solder points could be seen anywhere on the board.
After being very frustrated with a headlight issue last year, I ended up doing exactly what you mention. I removed the relay, but did not replace it. I opened it up to check the 8 total (4x2) contacts instead. Not even close to having any burned, I can tell you the relay is actually a solid component and not even remotely the weak point of the board. The weak points (addressed on the forum previously) are the two MOSFET's that control each motor. They're the ones riveted to the board. You would be surprised by how burned the board can be underneath them. Although some have found success in replacing those (I did replace them, but that wasn't my issue either), they aren't as common of an issue as one might imagine.
My issue turned out to be external to the board. It was either a battery connection or the ignition switch contacts. I am unsure which was the issue since I did them at the same time.
Last edited by vipmiller803; Feb 9, 2017 at 11:07 AM.
After being very frustrated with a headlight issue last year, I ended up doing exactly what you mention. I removed the relay, but did not replace it. I opened it up to check the 8 total (4x2) contacts instead. Not even close to having any burned, I can tell you the relay is actually a solid component and not even remotely the weak point of the board. The weak points (addressed on the forum previously) are the two MOSFET's that control each motor. They're the ones riveted to the board. You would be surprised by how burned the board can be underneath them. Although some have found success in replacing those (I did replace them, but that wasn't my issue either), they aren't as common of an issue as one might imagine.
My issue turned out to be external to the board. It was either a battery connection or the ignition switch terminals. I am unsure which was the issue since I did them at the same time.
So you replaced the ignition switch among other things?
So you replaced the ignition switch among other things?
I just took it apart and cleaned the contacts as recommended in one of the popular write-ups on this forum. I had to disconnect the battery to do that and noticed that one of the terminals had a little bit of buildup, so I cleaned the terminals at that time also. I am honestly not sure which was the issue, but that process fixed my headlight woes.
My point is, though, that the relay is very much so replaceable. However, I would be surprised to find that it is the root culprit. If your board was clicking repeatedly and the symptoms are corrected by a replacement board, you may be looking at an issue with the relay control circuit. The relay itself seems like a very nice unit, overbuilt for the application.
Last edited by vipmiller803; Feb 9, 2017 at 11:14 AM.
The weak points (addressed on the forum previously) are the two MOSFET's that control each motor. They're the ones riveted to the board. You would be surprised by how burned the board can be underneath them. Although some have found success in replacing those (I did replace them, but that wasn't my issue either), they aren't as common of an issue as one might imagine.
I spent a lot of time looking at the MOSFETs. On my board, they look good and show no sighs of burning. I cannot read electrical schematics but I am looking for a schematic for this module. What I want to energize the board to see of there is any arching inside the ice cube relay. Maybe that would be a telltale sign of a bad relay.
I seriously doubt you will find a schematic of the internal circuits for the HCM since that is most likely a GM proprietary component. I can take pics of the wiring up to the module from the C5 Shop manual and post those but they would require your interpretation of which of the leads (there are many) actually provide the power to operate the electronic components on the board. There are two always hot leads back to the head light motor fuses but there are also wires that pertain to the switching provided by the multi function stalk. Further this is not just one diagram but rather at least two separate diagrams.
I want to make the replaced module a project, to see if I can get it working again. Another member made a point that parts for these cars will become harder to locate, so that if a viable repair can be made, it would a good to know.
I sure agree....give it a go.
Pop up Headlight Module Relay Replacement
