Thunderbolt IV ignition module needed

[Rick Stephens]

Don't need to 'shotgun' repair. There is a flowchart that will identify the failed part in a few minutes...

Chris........

Chris,

The flowchart, in reality, has you start replacing parts at the cheaper end and working up to the expensive module. There is really no way to tell the difference, for sure, between a failed module and a failed pickup. Apple computers does the same ting in their service manuals. "if computer won't boot, replace power switch, if that doesn't get it, replace power supply" and so on down their list until the 'tech' replaces enough parts to get it up and running. And then everyone wonders why it seems every repair required a replacement motherboard.

I certainly could have missed something. And you have loads more experience than I will ever get with these Mercs. I build computer equipment for a living and that is how the flowchart looked to me.

~Rick

 

[JustJason]

There is really no way to tell the difference, for sure, between a failed module and a failed pickup.

​Well.... You can if you have a scope. Back when TB4's were considered "modern" nobody, and certainly no shop, had one. Nowadays each should have 1 tech that has a scope, or if the scope is shop property, a tech that knows how to use one.

 

[Rick Stephens]

​Well.... You can if you have a scope. Back when TB4's were considered "modern" nobody, and certainly no shop, had one. Nowadays each should have 1 tech that has a scope, or if the scope is shop property, a tech that knows how to use one.

Yah!

 

[achris]

.... There is really no way to tell the difference, for sure, between a failed module and a failed pickup...

Clearly on the flowchart... Check for 12 volts on the red/white wire on the sensor ("pickup"). No 12 volts, replace module. If 12 volts is present, remove the green/white wire and strike it on ground repeatedly. If there is spark, replace the sensor, if no spark, replace module....

That to me is pretty conclusive. I have also done extensive testing and analysing of the module (I was going to build duplicates at one stage) and understand how they work. The above is a very accurate way of determining what has failed. Of course what's above is only part of the whole chart, and ALL steps need to be followed.

Chris.......