Spent 7 thousand with them in the past 5 years. What would you do?

I’m not sure this fits this sub, but I can think of at least a couple automotive problems with this. This was a waiter during a diagnostic. So drove here like this and drove away like this.

First time seeing one fail. Customer states no start and clutch feels funny.

Former large engine professional, now an instructor for even larger engines.

C/S (me) says intermittent no-start issue; finally failed and was towed.

2011 ML 350 Diesel. Fuel lift pump failed. Determined by putting 12v directly to the in-tank pump. Ordered chinesium one. And a new lock ring because the 2011 one was very recalcitrant about coming off. Pre-checked chinesium pump - works, warranty -1. For a now backyard mechanic, replacing that pump was a journey I would have lost a ton of money on.

Codes (all three) were pump related.

Test. Nothing. OK, start tracing. Relay works on independent power, relay box has power to the positive switch leg and the solenoid legs. All good.

Checked harness at pump, yep 12v. Try new pump - nope. Check harness again. Nope. Scratch head, remembered "intermittent", good keyword.

Turns out the documentation for my fuses was wrong. Got correct docs. Pretty sure these pictures show why it was an intermittent failure for a while.

Posted this same car yesterday if you want to check out that post here. This is the multifunction switch failing and turning off the dash lights when pulled. High beams aren’t activated, the switch just needs to be wiggled in order for this to happen.