Yes I am probably going to have to do this. I am hoping to find an ATC style fuse holder with pigtails that will fit in between the existing clips in spot #8. I would either find a gap or drill a couple holes in the casing for the wires and hook them up on the back side.
In fact I am getting ideas about rebuilding the entire fuse box with ATC holders in this way. You could strip out the existing clips and leave only the terminals on the back. Then using ring tonge crimps, attach the pigtails from the ATC fuse holders to the appropriate terminals in the back. Then use potting compound to hold the ATC fuse holders in position.
You are right about the blower fuse, I will do no more than a 15 A ATC. I looked at the FSM wiring and the blower is fed from a 2.5 mm2 wire which is approximate to a 12 AWG. In my world that is a max 20 A fuse. However they also feed the a/c thermostat control and clutch relay and recirc flap actuator off a 0.75 mm2 wire which is approximiately #18 AWG which we cannot fuse at more than 7 A. (UL508a)
I also wonder what the contact point continuous and short circuit ratings for the ignition switch are. It's not just the continuous rating (thermal) but what happens in the case of a downstream short, you can weld the contacts if the fuse is overrated and can't clear in time.
I'm sure the Mercedes design standards were different and automotive is a totally different standard, both on this side of the pond and over there, than what I have to live with for control panels. But I still do
on some of the fuse ratings vs wire size, or the number of unprotected circuits straight from the battery.
I am seriously considering installing a fuse in the 6 mm2 line from the starter to the light switch. Way too scary for my taste to have unprotected power from a Group 85 battery running through the dash. Just have to calculate a size that would never trip under normal circumstances but blow in the case of a catastrophic short under the dash. I'm thinking in the 80 to 100 A range.
Unfortunately the regulator circuit for the alternator depends on this path, if the fuse were to open up you would lose regulation on the alternator. Although in that case you have isolated everything but the battery so you would not be operating in an overvoltage condition for very long as you would have no electrical system operating at all.
Anyone have access to a high capacity dc shunt to get some measurements of current on the system? I'm curious what some of the systems actually draw during operation. I have a cheap meter at home with a 10 A dc rating, I blew the fuse the other day checking out the blower before VStech fixed it.