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Indefinitely, and below is some commentary on how those "smart glow" fuses work. I've never used them myself, but it's the first thing that came to mind when you mentioned saving a few headaches and time to diagnose fuses:

rockets4kids:
A fuse generally blows when there is a short to ground and you will have 12V potential across the fuse leads. I'm pretty sure this is nothing more than a current limiting resistor and LED in series connected in parallel with the fusable link.

Anonymous:
It's simpler than that. When the fuse is good, there's almost no voltage drop across the leads. When the fuse is blow, 12V appears across the leads. Throw in a tiny incandescent lamp in parallel with the leads and it will glow when the fuse blows without providing any appreciable current to the circuit the fuse protects. You don't even need a short.​


EngineerVsMBA:
I'm betting they have two paths between the two sides of the fuse: one for high current, and the other path for the light. (High current will have low resistance, while the low current will have high resistance.)

When the fuse is together, both sides of the fuse sees 12v and the LED won't light up. If the fuse is blown, one side of the fuse sees +12v and the other sees ground. I'll bet if you connect a current sense to the fuse, you will see 10 mA flowing through the fuse, through the LED path. The low current path won't let enough current through to power any electronics, but it is enough to light the LED.

punx777:
Magic, got it.​

 

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Bought the ECS tuning Cooling system refresh kit with h2o pump Tstat, hoses and belts and 2 hoses came off while wife was driving it lost all the BMW coolant ( really its only Peak am I right) but $15 more a gallon. Then the belt slung off damaged the lower hose had to replace it. And we got the trans svc kit with redline oil and it shifted way better until recently getting a gear indicator warning light and it's shifting rough. Now that I got my Benz drivable I'll let the wife go through it and see can't I go all through this including the slow coolant leak developed after refreshing the cooling system. Leak appears under the intake manifold on 02 325i actual leak not spotted just evidence of it. What leaks under the intake manifold or is it leaking back from the Tstat, H2o pump? Anyone have similar develop? 144kmiles just replaced all 4 struts and 2 torsion bar bushing so suspensions tight just trying to spend the most cost effective $$ on it, or unload it.
 

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Discussion Starter · #347 ·
Bought the ECS tuning Cooling system refresh kit with h2o pump Tstat, hoses and belts and 2 hoses came off while wife was driving it lost all the BMW coolant ( really its only Peak am I right) but $15 more a gallon. Then the belt slung off damaged the lower hose had to replace it. And we got the trans svc kit with redline oil and it shifted way better until recently getting a gear indicator warning light and it's shifting rough. Now that I got my Benz drivable I'll let the wife go through it and see can't I go all through this including the slow coolant leak developed after refreshing the cooling system. Leak appears under the intake manifold on 02 325i actual leak not spotted just evidence of it. What leaks under the intake manifold or is it leaking back from the Tstat, H2o pump? Anyone have similar develop? 144kmiles just replaced all 4 struts and 2 torsion bar bushing so suspensions tight just trying to spend the most cost effective $$ on it, or unload it.
Could be the hard pipe or the o-rings for them.
 
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