Bypassing the Ammeter???

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roosduster

Colorado Mopar
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How do I go about bypassing the stock in dash ammeter? I plan on installing a gauge kit that comes with a volt meter and would like to bypass the ammeter. I have read many times on here it is a good thing to do but can not find out how to do it.

Thanks
 
You can secure both wires on one gauge stud. The volt meters supply should be a switched circuit such as the line that supplys 12 volts to the instrument panel. To tie anything in at the amp gauge would be a constant draw i.e. battery killer.
 
Thanks abodyjoe I am getting ready to rewire/upgrade the entire engine compartment and this will be a tremendous help.
 
RedFish said:
Or just put the 2 wires together .
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That is what I think I have heard. You disconnect the two wires from the gauge and hook them together and that way it just skips the gauge and then you just need to hook the voltmeter into a 12 volt switched source meaning when key is on it is on.
 
But- what if you want to keep the stock gauges? I have read that this ammeter is not safe as wired- is there a way to make it safe? For instance a headlight relay... I know it would not be an accurate gauge with that set up but it would be safer... and have the stock look... right?
 
I was just thinking about this today.I dont trust the old Ammeter gauge.The info on that site will help out alot and ill just put in a voltmeter instead.
 
jim in seattle said:
But- what if you want to keep the stock gauges? I have read that this ammeter is not safe as wired- is there a way to make it safe? For instance a headlight relay... I know it would not be an accurate gauge with that set up but it would be safer... and have the stock look... right?
Click to expand...

Nothing about the ammeter wiring is unsafe as far as the way it is intended to work. The problems set in when the multiple connections in the entire circuit loosen and corrode, usually from age. The full amperage of every circuit in the car passes thru the ammeter and the firewall connectors. This is the way ammeters work. you can't bypass it with a relay. Fusible links protect the ammeter circuit from shorts, but old and dirty high resistance connections can heat up, eventually causing burnt wires and possibly fire. This is why you see butcher jobs around the firewall connectors and fusible links where someone has tried to repair faulty connections. The firewall connection is underdesigned for the amperage required and adding accessories like big stereo amps will only make the situation worse. Best solution is to map out your primary alternator/ammeter/battery wiring with the largest guage wire practical and the minimum number of connections and splices. Of course, this would eliminate most of the stock wiring which is at odds with retaining a factory appearance. Sometimes you have to make choices.
 
Gryzynx said:
Nothing about the ammeter wiring is unsafe as far as the way it is intended to work. The problems set in when the multiple connections in the entire circuit loosen and corrode, usually from age. The full amperage of every circuit in the car passes thru the ammeter and the firewall connectors. This is the way ammeters work. you can't bypass it with a relay. Fusible links protect the ammeter circuit from shorts, but old and dirty high resistance connections can heat up, eventually causing burnt wires and possibly fire. This is why you see butcher jobs around the firewall connectors and fusible links where someone has tried to repair faulty connections. The firewall connection is underdesigned for the amperage required and adding accessories like big stereo amps will only make the situation worse. Best solution is to map out your primary alternator/ammeter/battery wiring with the largest guage wire practical and the minimum number of connections and splices. Of course, this would eliminate most of the stock wiring which is at odds with retaining a factory appearance. Sometimes you have to make choices.
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I Agree with Gryzynx. Also, a car owner adds a killer sound system, air conditioning, cooling fans, hid headlights,etc. Then he has to add a high- output alternator. That's when the problems start. If you want to keep the oem ammeter, you just have to keep your connections tight, and keep the add-on accessories to a minimum
 
A lot of us have cars of the same age that show no evidence of overheating in factory connections. I believe those horrible examples shown at madelectrical have a history of addons like 8 track, CB radios, fog lamps, or even wrecks. Messing around with the batt post on the altenator while the battery is connected would cause a melt down too.
Bottom line, we have the info we need to repair these faults but it's not a manditory upgrade for every car.
 
There has been a lot of discussion recently on electrical issues. I suggest looking at the other strings out there that are discussing their individual problems. It really comes down to a few issues.

Yes, think of the power coming from the alternator running through the bulkhead connector, and then going back out the bulkhead connector to the starter relay as one big loop. Inside the car, there are welded splices that feed power to the lights, radio, and ignition switch off that large black wire. Like it has been said, ALL the power for the car pass back and forth through these two large wires from the alternator to the battery... depending on the load that your car has.

So, there are a couple of actually easy steps (but time comsuming to do them correctly) that can be done to help relieve the strain on this single loop.

1. Make sure your original wiring is is good shape. Check for frays, poor/corroded connections (ESPECIALLY at the bulkhead connector- that is where most of the problems start), and butched wiring from years of modifications. Get this in shape before moving to anything else.

2. If you upgrade your alternator to a higher amp unit, you need to upgrade the wiring. The factory wires are not large enough to support what you may be trying to push through them. Since I knew I was going to add a 400W amp, new stereo and aftermarket A/C, I decided to add a chrome PowerMaster alternator to keep up. However, I knew that my stock wiring most likely would burn up if I didn't give it some attention. To relieve the strain of the charging system (power coming from the alternator), add a decent size wire (10 gauge or larger) from the power + post on the alternator (around the harness) back to the large post on the starter relay. Make sure to use an appropriate size fusible link on this wire before connecting. What that does is provide a straight shot to the battery for charging that has NOTHING else pulling from it. It also takes a little bit of the strain off your interior wiring. See my modified diagram below.
attachment.php


YES, take note that once this wire is added, your amp gauge will not work properly anymore since the amp really measures the charge/discharge that the car is receiving. But that was the point of this anyways right?

3. Right now all your power for your headlights comes from the headlight switch inside the car. The 12 volts has to make a VERY LONG path in small wiring from that switch to the headlamps. That will cause dim headlights (especially if that bulkhead connector connection is a problem). Moving your headlights power to a relay system really improves their ablity to function correctly, PLUS the headlight switch no longer has to provide a large amount of power straight to the headlamps, but just the little (probably no more than .3 amps) to just turn on and off the relays. Ideally, you would power the new headlamp relays straight from that large battery post eliminating distance and giving you the ablity to wire those relays again with a decent size wire. Your headlamps will work 1000% better and again, load will be taken off that interior wiring. More information can be found here:

http://www.danielsternlighting.com/tech/relays/relays.html

Here is what my relays look like... I hid mine under the battery tray. (I have fog lights, that why there are 3 relays).
relay_box.jpg


4. Aftermarket A/C or car stereo amps need their own new power wire (with correct fuse/circuit breaker) from that large post on the starter relay (starting to see a pattern?) Use quality wire and fuses and make sure to protect any connections from the elements (heat shrink, etc.)

Good luck! Remember, there are many discussions on this that have already occurred and can be found by just doing a search in the electrical forum.
 
RedFish said:
A lot of us have cars of the same age that show no evidence of overheating in factory connections. I believe those horrible examples shown at madelectrical have a history of addons like 8 track, CB radios, fog lamps, or even wrecks. Messing around with the batt post on the altenator while the battery is connected would cause a melt down too.
Bottom line, we have the info we need to repair these faults but it's not a manditory upgrade for every car.
Click to expand...


RedFish brought up a great point. If your car is basically stock and in really great shape (electrically), then there is no reason to mess with anything. If you plan on some serious upgrades such as higher output alternator, big stereo, A/C, etc. Then you need to consider what you have to do to bring that old wiring up to the level it needs to be to support those additions. Good luck. Hope we have helped.
 
The only aftermarket electricals my Duster has is the tach,a set of gauges,and just a low power am/fm cassette.So I shouldnt have to worry about this?I dont have AC or need a high power stereo or anything.
 
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