GM5 DIY Repair

[poss]

Given I live in the arse end of the world and parcel deliveries are particularly problematic ATM I decided to replace/resolder my Zed's GM5 relays myself.

I saw a number of youtube videos with people using desoldering guns - and it seemed they all ended up having to fix damage to the circuit board as a result (it's a double-sided circuit board).

Instead I used ChipQuik, a low melting point metal that lets you heat up all the solder on the pins on the relays until it can easily be removed without damage to the circuit board tracks. It did both relays without any damage. Took about an hour to do the full repair - need to clean up holes with flux and solder wick after removing relays of course (only the first relay removed in pic - both need to be removed).

 

[Zulu4]

Interesting. Very well done

 

[poss]

Interesting. Very well done

Thanks. Hope its useful for those with the skills to attempt and can't easily send off to have it done professionally.

In the pic you will see 2 solder pads in top left of relay mount with very fine tracks leading to them that are very easily damaged, and the others have large double-sided copper traces that make traditional desoldering difficult unless you have high end equipment. With ChipQuik you know when each pin's solder is completely liquid because you can easily wiggle the pin with the tip of your soldering iron. The pins surrounded by large copper traces need more heating time.

350 Celsius was an effective soldering tip temperature that didn't damage the board.

Once all the pins can be wiggled with the soldering tip gently pull on the relay and it should pull out easily.

 

[spazmochad]

I think there were a couple of issues with technique of the guy with the de-soldering gun in the video I saw.
The default nozzle size that comes with it is too big for the pitch used on the PCB. I have the same gun and had issues until I swapped to one with a smaller diameter on similar through-hole boards. The gun's also needed to be cleaned out regularly as they tend to clog and take too long otherwise.
I'd also have used a soldering iron with leaded or low melt solder before going in with the de-soldering gun.
Nice work doing this with Chipquik, it must work pretty well, you didn't lift any pads with the wiggling!
Need to do mine whilst the glovebox is out, how does the module pull out from the metal bar?

 

[poss]

how does the module pull out from the metal bar?

In my 2003 3.0i the GM5 is mounted on a bracket that is bolted to the sidewall behind the glovebox with 2 studs next to each other- each with a 10mm hex nut. I was able to get to these nuts with a 10mm spanner without removing the glovebox (just the panel below/behind it). The module will then drop out with bracket attached

 

[poss]

PS: Just reinstalled repaired GM5. Remote access lock/unlock now working perfectly!

 

[Ewazix]

Nice work and an interesting development for the tricky de-soldering process if you can't send your board off as most of us have done until now

https://z4-forum.com/forum/viewtopic.php?t=102586

 

[poss]

Nice work and an interesting development for the tricky de-soldering process if you can't send your board off as most of us have done until now

https://z4-forum.com/forum/viewtopic.php?t=102586

Necessity is the mother of invention. I design and build audio systems and recently used ChipQuik to remove dodgy speaker relays. It was so easy to do I decided to give it a go on the GM5 relays. No Problemo - and no specialist equipment needed to get a perfect result. Unsurprising as I've taken off 100 pin LSI chips with absolutely no damage to very fine circuit traces, but good to see it's very effective for thru hole component removal too.

 

[jabber]

Great work

 

[Scooba_Steve]

PS: Just reinstalled repaired GM5. Remote access lock/unlock now working perfectly!

What symptoms did you have?

 

[poss]

PS: Just reinstalled repaired GM5. Remote access lock/unlock now working perfectly!

What symptoms did you have?

Car would remote lock but remote unlock on both doors was intermittent - then stopped working entirely (same if you pressed center console button to unlock). A guaranteed sign its a GM5 problem (which it was)

 

[Scooba_Steve]

Car would remote lock but remote unlock on both doors was intermittent - then stopped working entirely (same if you pressed center console button to unlock). A guaranteed sign its a GM5 problem (which it was)

I currently have no response to any remote control. Don't mind sending the GM5 off, just don't want to send it off and it not fix the problem.
Car unlocks fine from the key in the door and centre console button.

 

[poss]

I currently have no response to any remote control. Don't mind sending the GM5 off, just don't want to send it off and it not fix the problem.
Car unlocks fine from the key in the door and centre console button.

The centre console button operates the GM5 - so if it works fine it's not the GM5 relays (my centre console button wasn't working either and the repair fixed this). Sounds like a remoting issue.

My lights flash when I press any button on my key - so I knew it wasn't a problem with receiving the remote signal and therefore it was almost certainly the GM5 as both doors were similarly affected (not a door actuator).

Have you tried the procedure to re-associate your key remote with the car? If that doesn't work then its either the battery in your key or the receiver in the car. I had a prob with the receiver in my E46 - I fixed it by unplugging and re-seated the connector to the receiver in the rear-view mirror a few times.

 

[Scooba_Steve]

The centre console button operates the GM5 - so if it works fine it's not the GM5 relays (my centre console button wasn't working either and the repair fixed this). Sounds like a remoting issue.

Thanks, that is a big help.

Have you tried the procedure to re-associate your key remote with the car? If that doesn't work then its either the battery in your key or the receiver in the car. I had a prob with the receiver in my E46 - I fixed it by unplugging and re-seated the connector to the receiver in the rear-view mirror a few times.

I'll try both, had changed battery (replaceable in a different key type) and also using original key after a journey to charge it with no joy. So at least I know where to start looking.

 

[poss]

The coding can get out of sync and this stops the key buttons working. When I r-associated my E46 keys they worked for awhile then stopped - turned out to be the bad connection to the receiver in the mirror causing intermittent connectivity issues that caused the key to get out of sync. Apparently the vehicle and key cycle thru a set of codes so that someone cannot simply listen with a scanner and copy the access code.

If for some reason they don't do this in lock-step the buttons will stop working.