Wire hot to the touch

[Fastz06]

Guys,
I was working under the dash and touched the 10 Ga yellow wire that runs from the alternator to the ammeter and it was too hot to touch. Smells too.

Does this mean the ammeter is going? I'm afraid to drive it like this...
Can I test the resistance of the ammeter?

Thanks

[tcrist]

Does it only do this after running or with the key off and not has been running? If it is only like this after running then you need to check it out at your leisure (don't drive it of course). If it is just sitting there and has not been driven but the wire is hot to the touch, unhook your battery and get someone to look at it.

I would not be sure but it sounds to me like the alternator is putting out too much power to the gauge. Bad alternator maybe? As you say the wire is coming from your alternator then my guess is that you have an internal regulator and that might be bad. I am no professional by any means. I am sure someone else here can help better than I.

Terry

[patrickt]

Originally Posted by Fastz06

Can I test the resistance of the ammeter?

That won't tell you what you want to know. I'm going to assume that your ammeter is not reading +100 the whole time you're running. If you were to put an ohm meter across your ammeter the resistance is going to be zero even if it is acting "like a skinny little wire" when really it should be "a reasonably fat wire." If you were to test it, you would need to put a measured load (watts) in a circuit along with the ammeter and your measured voltage. That's a PITA. What I would do is check the connections on your wire and, assuming you don't find anything loose or wiggly, put a ten gauge jumper wire securely across the terminals of your ammeter -- that will effectively negate your ammeter. If your wire heating problems then disappear, replace your ammeter. Make sense?

[Blas]

A loose connection can cause heating in the wire too, so check both ends of the wire and the crimps. But as was mentioned, your voltage regulator may be the problem. Easy enough to test, just get you volt meter out and start the car, and check the output. Should be 13.8 to 14.2 volts...How's the fluid level on your battery. Many times, overcharging with boil out the battery liquid, and you get an acid smell too... Correct this before driving or you could be rewiring melted wires all over the car...

[vettestr]

What is the gauge showing the charge or discharge rate is? I ask out of curiosity as the wire and gauge should not be hot if 10 or 60 amps are displayed but a 60 amp discharge may be a clue to a major discharge or load downstream.

With the key on but engine not running the gauge display should be about zero. Check to see if wire heats up with key in on position but not running. Note display and if anything is running or not running that should be. Removing a fuse from items like fuel pump should stop remove discharge showing on the gauge.

[PANAVIA]

Could be just tooo muuuch stuff -- Fans and lights can add a lot of load, not to mention MSD boxes. --

[Fastz06]

Thanks for the ideas guys
I disconnected the battery until I can check it out.

[RICK LAKE]

Fastz06 you have a message

[Joe Wicked]

A hot wire has too much current going through it for it's size. This can be caused by having too much powered by the system (overloading), or by a bad component loading to ground. Bypassing the Amp gauge will tell you if it is the gauge, but I would think that it would be something else down the line. I had a similar problem on a 460. Turned out the Starter Solenoid was getting stuck. This created a huge load on the system and was burning up the wire. I shut off the truck and smelled something burning opened the hood and found the same wire you have getting hot on fire.

If you have a good multimeter, you can disconnect the Ammeter and use the Ammeter function of the multimeter to see if it is reading correctly. Be careful though as if it is from overloading you can damage the meter if you don't have the settings right.

[CHANMADD]

This is the reason that manufacturers stopped using an ammeter and went to using a Volt Meter. I had a car catch on fire once because of an ammeter.
John

[Ronbo]

Pick up a current indicator off ebay or NAPA. These lay across the wire and show you how much current the alt. is generating (load matching). I have a set of these from Snap-on, don't waste money on the digital ones that may or may not work three years from now when you need to check it again. My Snap-on's have always worked when I needed them over the past 20yrs unlike the 6 DVMs I've been through. (My Simpson 260M still works like a charm as well)

How big is your alternator? 10ga is not big enough for anything above 60A.

Although the voltmeter is more critical with today's electronic stuff like ignitions it doesn't really replace the amp meter. (ideally you'd want both in my view)

[Joe Wicked]

Originally Posted by Ronbo

How big is your alternator? 10ga is not big enough for anything above 60A.

Very good point that I did not mention. Goes to the overloading category, but you don't always have to have too much pulling current. You could be producing too much for the wire.

[kobrabytes]

Your wire is to small:

http://www.cerrowire.com/default.aspx?id=46
http://www.powerstream.com/Wire_Size.htm

I run a #8 from my alternator, although #6 would run cooler.

[patrickt]

Originally Posted by kobrabytes

Your wire is to small:

http://www.cerrowire.com/default.aspx?id=46
http://www.powerstream.com/Wire_Size.htm

I run a #8 from my alternator, although #6 would run cooler.

But those numbers are for steady current. My amp gauge, like most of our cars, shows its highest current right after starting the car while it's charging the battery -- and even then it's under 20 amps and only for a relatively short while. If your amp gauge is reading consistently over 5 amps all the time then you have a problem. The amperage running through the charging wire is usually very low almost all the time.

Afterthought -- The hghest amperage might be hit though when the fans are still running after the engine has been turned off.

[strictlypersonl]

The easy way to determine the major problem is to compare the temperature along the hot (temperature) wire. If the temperature is relatively even along the length, there is a high current draw. If the wire is hot only in a small section, then the problem is in a connection or (not likely) a partially broken wire.

[RICK LAKE]

Fastz06 Fast here is a easy fix for your hot wire problem, I am going with the fact that you have good grounds on the motor and chassic. 2 from the motor to the chassic, 2 from the battery ground to the frame and motor if the the battery is under the hood. Next you need to run a RED #4 gauage wire from the pos+ of the ALT out put to the battery. This will stop the over load of the amp meter and cut out the heavy draw. The amp meter will still work for any amps being used through this power feed. The battery is getting a direct recharge through the #4 wire. This will save the meter. The other idea is to replace the amp meter with a volt meter. You will still have to do some wiring for this to work. A voltmeter makes more sense than and AMP meter but is not orginial to a cobra. The other problem is how much ampage is being run through the meter. 30-40 amps is OK, more than this, is not the best way. I am going from a 70A alt to a 130 amp (3G) setup. I am going to a voltage gauge also. At Idle what does your amp gauge read about? with the basic electrical in a cobra, lights,3 fans, blower motor, and an MSD setup you are at the limit of the charging system at 55-60 amps. MSD system with HV coil uses more than 6 amps at 6,000 rpms, more like 12-15 amps. Rick

[Joe Wicked]

Glad you found it. Were the wires melted through?