[200q20v] radiator fuse - failsafe

QSHIPQ at aol.com QSHIPQ at aol.com
Wed Feb 28 17:06:45 EST 2001

NO.  The problem with a circuit breaker, Bernie, is that it will continue to 
reset, which will fry the wiring of the rest of the car if you don't address 
the problem right away (as in disconnect the battery).  The issue is that the 
startup and function of that motor is at a very high amperage when the motor 
is running.  That means when it isn't, a circuit breaker can cause a lot of 
damage before the "actual" problem is corrected.  One could argue the fuse is 
like that too, but the fuse can only blow once, causing you to either take 
immediate action or the head gasket blows.  Still given the two evils, mucho 
cheaper than frying wires.  I rerouted one set of wires, on a car with a 
bypassed fuse link.  That was no fun, and took forever (oops, here's another 
connector fried I have to order).  A head gasket is a day job at most.

Not with you on this one.  IMO, Chris M has the better idea, just service the 
fuse that's exposed to all elements, for 20USD for *all* parts associated 
with it, doing it every other year is cheap.  As far as a 'test' circuit, I'd 
T off the starter line with a bulb in the dash (upshift indicator?) that 
grounds thru the fuse.  The light turns on with the starter when you have 
good ground, goes out when you release the ignition switch.  The advantage of 
this is that the circuit is open if you get any feedback 12v when the fuse is 

My .02

Scott Justusson
In a message dated 2/28/01 3:54:15 PM Central Standard Time, 
b.m.benz at prodigy.net writes:

> Hey, you guys.  Stop replacing junk with more junk!  Better to replace the
>  fuse with a self resetting circuit breaker and a line to the brake fault
>  indicator, such that the light will flash when the CB is open.  The circuit
>  braker can probably be sized for the steady state motor running current,
>  inasmuch as its lag time may be sufficient to not trip on the motor 
>  current.
>  Bernie

More information about the 200q20v mailing list