Circuit breakers!!

[DeLorean]

So my 35 amp rad fan breaker was tripping causing a hotter than normal engine temperature, and as a temporary fix, I put a 30 amp fuse in it's place. So far, it has not blown, and I have done 400 miles in the past 2 days, - the hottest day of the year so far with the AC on!

Is this an appropriate fix to make permanent with a proper fuse holder, or should I order a new CB? In this instance, I'd probably also do the same for the blower motor...

[Farrar]

What do you have in your "fan fail module" socket? If you have two fuses (one for each fan), you can throw the circuit breaker away.

Farrar

[DeLorean]

ATM, I have the 3 wire fan fail bypass in that socket.

[Farrar]

Don't you mean two wires? It's usually of a Y-shaped jumper, with two wires and three spade terminals. Anyway, most users have this Y-shaped arrangement, but with an inline fuse of 20 amps on each "leg" of the "Y." If you do that, you can eliminate the circuit breaker.

HOWEVER... I would first make sure that your fans aren't drawing too much current. If they trip the circuit breaker under normal operating conditions, you may have corrosion on the brushes or something else causing the fans to pull too much current. If they're pulling too much current, then a 20-amp fuse on each fan will also be no help.

Which fans are installed on your car? If they're original, that might be your problem.

Farrar

[DeLorean]

Aah that makes sense. The rad fans are still original (for now) and being that they have not blown a 30 amp fuse running for hours at at time, and also still spin freely, I am assuming they are fine.

I do intend to replace them with one of the lower amperage replacement units - but for now, I like that solution. No breaker, and a 20 amp fuse on each leg on the "fan fail" jumper.

[Bitsyncmaster]

You should have a 40 amp breaker for the cooling fans. But like Farrar suggested, use the twin fuses and get rid of the breaker.

Your 35 amp breaker is no good if you can run a 30 amp fuse without blowing. I'm not sure if you can get a 40 amp fuse in those blade types but if you can, use one. I bet that 30 amp fuse it running very warm when the fans are running.

[DeLorean]

The 30 is running rather warm for certain. And yes, the "short stop" 35 amp breaker is no good, because it trips constantly if it's installed, and a 30 amp fuse works fine (though it does run warm)

So acceptable solutions are a 40 amp fuse in place of the breaker, or no breaker (bridge the terminals) and install a pair if blade fuses & holders on each leg of the "fan fail" bypass.

[Bitsyncmaster]

The 30 is running rather warm for certain. And yes, the "short stop" 35 amp breaker is no good, because it trips constantly if it's installed, and a 30 amp fuse works fine (though it does run warm)

So acceptable solutions are a 40 amp fuse in place of the breaker, or no breaker (bridge the terminals) and install a pair if blade fuses & holders on each leg of the "fan fail" bypass.

Yes. Either or, you don't need both.

Edit:
But the double 20 amp fuses are better. With the single 40 amp, if you had one fan get an open circuit, then the other fan will only blow the fuse if it draws more than 40 amps.

[Chris 16409]

Dave, what do you do with the wires once you take them off the circuit breaker? Do you just splice inline fuses between the striped and brown battery wires? Does the dual fan relay mod affect the way this works?

[Bitsyncmaster]

Dave, what do you do with the wires once you take them off the circuit breaker? Do you just splice inline fuses between the striped and brown battery wires? Does the dual fan relay mod affect the way this works?

What I did was completely remove the wires and the breaker. The wires run all the way to the right side bundle and then back to fan fail socket (about 6 foot of wire). I used a 4 inch jumper with crimped pins installed from the fan relay to the fan fail relay. I will send that jumper when you buy the fan relay and fan fail units.

Since your dual fan modification does not fuse each fan, you would not want to remove the 40 amp breaker.

[DeLorean]

SO the fan fail is now replaced with 2 fused legs on blade fuses, and the old CB is gone, fans work good now.

The other 2 CB's are for what? The one is clearly for the interior blower motor, but it has 4 wires going into it. One pair from the selector one pair to the fan?

The 3rd one, mounted further back in the panel is for what?


Both the interior blower and the ? CB were 25 amp "short-stop" CB's which I have replaced with 25 amp blade fuses.

[TTait]

You should have a 40 amp breaker for the cooling fans. But like Farrar suggested, use the twin fuses and get rid of the breaker.


I'm using a fanzilla, which has dual glass fuses - I presume I can remove my CB as well - right?



SO the fan fail is now replaced with 2 fused legs on blade fuses, and the old CB is gone, fans work good now.

The other 2 CB's are for what? The one is clearly for the interior blower motor, but it has 4 wires going into it. One pair from the selector one pair to the fan?

The 3rd one, mounted further back in the panel is for what?


Both the interior blower and the ? CB were 25 amp "short-stop" CB's which I have replaced with 25 amp blade fuses.



See the post by Jonathan on 7/11 here...

http://dmctalk.org/showthread.php?40-All-Wiring-Schematics

[Bitsyncmaster]

The blower breaker (should be 30 amp) also is a terminal power point for the starter solenoid through the "starter relay modification". The two load side wires go to the two blower relays.

With a fused (or circuit breaker) in your door lock controller, you would not need the door lock breaker which would also be redundant.