The Lotus Cars Community banner

1 - 15 of 15 Posts

·
Registered
Joined
·
95 Posts
Discussion Starter #1
I've installed a Speedcom intercom on my track Elise (2005 Federal) to allow better driver to passenger communication. (first one on that list : Intercoms | speedcom-racing)
It can run on battery but also on 12V. I've plugged it on the auxiliary power socket source, but keep blowing the 20A fuse every time I start the car. (F1)
I don't have much electrical knowledge, any idea where the problem could be?

1265789
 

·
Registered
2006 Lotus Exige
Joined
·
57 Posts
I have the same problem on my 06 Exige. I plan to rip into it this coming week. I will let you know want I find, maybe it will help you. The fan for me supercharger IC is on the same circuit. All is fine till I plug something into the the power outlet. I am sure it’s a short in the plug.
 

·
Premium Member
Joined
·
2,654 Posts
I think if you pull the liner out of the 'cupholder' you can see the wiring to the power outlet and see if it is shorting against the chassis
 

·
Registered
Joined
·
95 Posts
Discussion Starter #4
@06LE let me know what you find!
I actually don’t have either the cup holder or the power outlet, (handbrake removal), just 2 wires I connected to the intercom. I’ll double check that connection...
 

·
Less is Better
Joined
·
2,627 Posts
Do you know how much current it draws? It might be legitimately blowing the fuse.
 

·
Registered
Joined
·
962 Posts
The documentation for the intercom system should show the current draw. I kind of doubt that is the problem though. As you said, it runs off of 2 AA batteries if you don't plug in so I would assume it has a very small current draw. You may want to plug in something else like cell phone charger and see if you have the same problem with a different accessory. I see that the intercom did not come with a plug on the end of the harness. Can you provide pictures of your installation and a closeup of the wiring where you connected it? It might be the cigarette lighter connector if you put your own connector on the end of the wire.
 

·
Less is Better
Joined
·
2,627 Posts
The specs for the intercom should have current draw. You might also be able to measure it with an ohmmeter.

R=V/I if R is less than 0.6 ohms you'll draw too much current, assuming there's nothing else on the circuit. That may not work though.

The intercom might also be internally damaged. Does it work in a different car?
 

·
Registered
Joined
·
95 Posts
Discussion Starter #9
Unfortunately I can’t find those specs, but I’ll contact Speedcom.
Here is the installation, Intercom is mounted between the seats on the roll cage. There are 2 electrical connection points, both look clean. Intercom works fine where running on 4x AA.
1265853

1265855

1265856
 

·
Registered
Joined
·
962 Posts
Wiring looks clean but what is in the tank behind the seat? That looks more interesting....
 

·
Registered
Joined
·
962 Posts
Very nice. I was hoping you were not sitting on a nitrous tank. Just the opposite actually, good.
 

·
Registered
Joined
·
92 Posts
Does it work at first, then the fuse blows when the car is started? Thst wire should be connected to the battery, always on. If it blows as soon as the battery is connected, it's probably a simple short, if it only does it after or during start up it is either a vibration causing a short, or something back feeding. If the control module has an open back it could short through that. When an item is run by its own batteries if the positive terminal of those aa Batts touch ground, nothing will happen, but then you connect it to the cars batt then it has two points touching the cars electrical system. The first step is finding the exact conditions under which the fuse blows. If you want you can make a simple test rig with a light bulb taking the place of the fuse. Take a 194 bulb and either bend the wire terminals from it to replace the fuse, or put a similar bulb in a bulb holder then crimp an uninsulated quick disconnect to either wire. The bulb used should draw more than the item load, eg a small fan should be tested with a headlight bulb, but something small like you have should only need a side marker (194) or tail light bulb (3556?) at most. When the item is working normally the bulb will be barely lit, but when it's shorted out the bulb will light fully. If the bulb lights fully constantly, a higher wattage bulb may be needed, or the thing is constantly shorted. Doing this you can sometimes shake an item or wiring and see the bulb suddenly light up, indicating where the issue is.
 

·
Registered
Joined
·
92 Posts
And as someone who has done a lot of wiring and rewiring, including a few complete rewires on street cars. Not to mention my Elise k20 swap with all the wiring from the rear back replaced (minus the lights). That looks as clean if not cleaner then I'd consider correct. The "cleaner" is due to the hear shrink butt connectors, not necessary as it's in cabin, but definitely doesn't hurt.
 

·
Registered
Joined
·
95 Posts
Discussion Starter #15
Does it work at first, then the fuse blows when the car is started? Thst wire should be connected to the battery, always on. If it blows as soon as the battery is connected, it's probably a simple short, if it only does it after or during start up it is either a vibration causing a short, or something back feeding. If the control module has an open back it could short through that. When an item is run by its own batteries if the positive terminal of those aa Batts touch ground, nothing will happen, but then you connect it to the cars batt then it has two points touching the cars electrical system. The first step is finding the exact conditions under which the fuse blows. If you want you can make a simple test rig with a light bulb taking the place of the fuse. Take a 194 bulb and either bend the wire terminals from it to replace the fuse, or put a similar bulb in a bulb holder then crimp an uninsulated quick disconnect to either wire. The bulb used should draw more than the item load, eg a small fan should be tested with a headlight bulb, but something small like you have should only need a side marker (194) or tail light bulb (3556?) at most. When the item is working normally the bulb will be barely lit, but when it's shorted out the bulb will light fully. If the bulb lights fully constantly, a higher wattage bulb may be needed, or the thing is constantly shorted. Doing this you can sometimes shake an item or wiring and see the bulb suddenly light up, indicating where the issue is.
Thanks this is very helpful information. The fuse blows as soon as I push the Start button, so there must be a short somewhere. Just need to follow the wires!
 
1 - 15 of 15 Posts
Top