how to spot a blown fuse

[Fireball]

As the title suggests, I'm trying to come up with a way of detecting a blown fan fuse. As the initial current on my fan is 16A and then quickly stabilizes to 10A, I'm thinking the 15A fuse could blow or even just get dirty and not make a connection. It would be nice to have a buzzer or warning light if this fuse blows as I may not register a rising temperature until too late. Any bright sparks out there please give me a buzz.... (couldn't resist, sorry).

James

[catsx11]

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[Fireball]

Hi Alan,
As you say, I think a buzzer would be the way to go as I can hide it but how to wire it....

[clive]

Hi Alan,
As you say, I think a buzzer would be the way to go as I can hide it but how to wire it....

.... Or hear it???

[nikbj68]

We have an illuminated switch on the Greyhound which also lights up when the fan cuts in thermostatically, maybe you could rig something like that?
Is the fan circuit switched by the ignition? How long would it take a relay(for a warning lamp or buzzer) to flatten the battery when the car isn`t in use?

[Karl]

You need a relay with a NC contact, coil + connected with the + wire to the fan, so the relay is activated the same time as the fan. The NC contact is open. When your fuse goes bad, + to coil is lost and relay drops out, NC contact is closed, which brings on your buzzer or light, which is supplied from a different circuit (ignition on)
Happy wiring!
Karl

[Karl]

Sorry, I just have seen you asked the same question in the cobra forum and did get the same answer.
"Doppelt genaeht haelt besser!" as we would say over here!
(Double sewing holds together better)

[Fireball]

Hi All,
the fan is wired from permanent live although I think you have it Karl! I think you may be right about hearing the buzzer but I'll only really need the fan when the car is stationary or going very slowly (so it shouldn't be too noisy). I really don't want to mess up my dash with a light although it might be the lesser of two evils. Now to the batcave to find a relay and somewhere to hide it...
Thanks gents.

[Karl]

I would recommend to run the fan also via a relay. The coil of this relay should be activated when ignition is on and temp. switch has closed its contact. I have two fans, one relay each, never had a problem in 5 years. It is also very easy to add a manual "on" switch to energize the coil.