This is actually a factory-supported upgrade. The W123 (and possibly some other chassis - 126?) had a problem with the ACC blower fuse popping because actual load was too close to the fuse rating (25A). The fix is to bypass the original ceramic fuse with an external 30A fuse. The factory fix uses a flat fuse that looks like the glow plug fuse (but rated 30A instead of 50A or 80A, depending on your engine). I used an aftermarket GM-style fuse holder and it works great - no more problems. Previously I had to change the stupid fuse every month or so.
Note that this is ONLY for the ACC blower fan, and is ONLY allowed with a properly installed 30A fuse. Early W124's had the 25A ceramic but from the mid-1987 model year through 1995 they all got the external 30A from the factory. Outside of this scenario, installing a larger fuse than specified is a great way to burn your car down, and possibly provide some entertainment for the neighbors & local fire department... ;-) -Dave M. > ------------------------------ > Date: Mon, 29 Aug 2005 12:07:02 -0400 > From: andrew strasfogel <[EMAIL PROTECTED]> > Subject: Re: [MBZ] 84 300Dt Climate Control > > In theory, yes, but in practice, this is a non-issue. Two years of driving > with the "wrong" fuse and I'm still here to write about it. > > > On 8/29/05, Steve MacSween <[EMAIL PROTECTED]> wrote: > > > > Woah, there, guys, it may only be 12 volts (as opposed to household > > electrics), but putting in too large a fuse is the least practical way of > > getting around the problem, does not 'fix' anything. Plus if you cause > > yourself an electrical meltdown in the harness and claim on insurance, you > > can be sure the first thing the adjuster will check will be the fuse > > ratings. > > > > Mac