Alternator Bypass Wire Routing

[Poolshark314]

I have read many of the threads on multiple forums for this topic and while there are some diagrams, I haven't seen anyone post actual pictures of the alternator bypass, so I thought I would start a thread to help future clueless people like me. Ordered a 6ga cable from @crackedback  (Thanks Rob), so I know I need to go from the alternator stud to the starter relay. What is the route people generally take to get there? Just following the original route of the smaller gauge cable until you get to the firewall and continue on to the starter relay?

After that, I know I can leave the original wiring in place so it is running in parallel. I will then work on seeing if I can get under the dash, disconnect both sides of the ammeter, and wire them together on one side of the ammeter. Is this still the recommended action to perform the bypass? If reaching back up to the gauge becomes a pain, is just taking both ends, connecting them with a separate nut and bolt, then wrapping the whole connection in tape acceptable since it is an inline connection?




Updated to show steps and options:

   
• Disconnect the negative terminal of your battery to remove power and avoid unnecessary risk
• Choose and mock up your route - The 2 most popular routes are:
  
  
        
  • Roughly the original route - Following the original alternator cable across the intake manifold and around the back of the engine, but continuing around the driver's side fender to the starter relay instead of through the firewall (see Alternator Bypass Back Route.jpg)
  • Run Towards the Front, the idea being the cable is further away from heat - From the alternator over to the passenger side fender forward to the front of the radiator support, through an existing hole on the driver's side, under the battery tray and back up to the starter relay (see Alternator Bypass Front Route.png)
• Lay the cable in the proposed route to ensure you have enough length. The thicker 6ga or 8ga end connects to the rear terminal post of the alternator. The smaller 10ga or 12ga end (orange in my case) with a built in fusible link connects to the positive terminal of the starter relay or battery itself.
• Carefully lift off the protective boot on the back of the alternator terminal, then loosen and remove the nut with a 7/16" wrench. Add the new cable and tighten the nut back onto the alternator (see Alternator end attached.jpg). Slide the protective boot back down over the nut.
• Run the cable properly through any supports/loom in your desired route. Do not fasten or ziptie in place until starter relay connection complete.
• Loosen and remove the nut on the positive terminal of the starter relay using a 1/2" wrench. Add the new cable and tighten the nut back onto the starter relay terminal (see Starter Relay end attached.jpg).
• Fasten the rest of the wire using zipties to supports or loom.
• Reconnect the negative terminal of the battery and test
• Finish your beer

At this point, you have now removed the bulk of the power load from the stock wiring harness through the firewall. It is a good idea to also disconnect the ammeter leads, connect them together with a nut and bolt, then wrap them in tape to protect them from contacting the grounded firewall.

[Jay Bee]

I got no input on the routing but, after tracing my wiper wire issue, I can say that I was able to easily see the ammeter connections when I was on my back. Highly recommend removing the driver's seat first and maybe a pillow for your head.

[crackedback]

I prefer not having anything attached to the ammeter.   Connect the two wires with a separate nylock and machine screw and wrap it.

Your painted routing is exactly how 99% of the people run it.   Hides in the factory harness easily.

[Dakota]

  The path you marked is the same one I used.

[GrandpaKevin]

I have the bypass wire on both our Challengers.

I have it routed like you pictured.
It hides easily with all the factory alternator wiring between the intake and valve cover then goes through the firewall loom and across the firewall with all the factory wiring then up to the solenoid. A few zip ties and the wires disappears with the factory wires.

If you look real hard you can see the wire, it is the bigger diameter black wire.

[mopar jack]

I decided to run my bypass wire from the alt to the front radiator yoke and follow the head lamp wires to the start relay. The wire harness along the pass side valve cover gets a lot of heat and figured if the wire ever melted it would  be away from the engine compartment.

[Scooter]

I decided to run my bypass wire from the alt to the front radiator yoke and follow the head lamp wires to the start relay. The wire harness along the pass side valve cover gets a lot of heat and figured if the wire ever melted it would  be away from the engine compartment.

I did the same... seemed logical to keep the wire off the top of the hot intake/valve cover.

[chargerdon]

I ran my bypass wire thru the radiator support, across right under the lip, and then back thru the radiator support and under the battery tray to the starter relay.    I already had run the "batter direct" wires for my air conditioner there anyways and it is the shortest route and away from any heat of the engine. 

Regarding the ammeter.    Leaving it connected doesn't hurt anything as the huge bulk of the current is running thru the bypass wire.   However, it also will no longer be the least bit accurate.   So, i removed it and was able to replace it with a Voltmeter.   I believe it was a Sun voltmeter.    The wiring for it is from the two wires now connected together where the ammeter was, AND a separate wire to dash ground.   So now if i turn the key to Accessory, i can see what the battery voltage is...usually between 12.2 and 12.6.   Or turn it to ON without starting the car and i get about 11.5 volts as the Coil, ECU, Voltage regulator, and Choke heater all pull down its voltage.   Of course when the engine is started, and idling it will show about 12.5 volts for about 10-30 seconds before reaching and maintaining 13.5-14 volt.     Kinda neat !!

[Poolshark314]

I ran my bypass wire thru the radiator support, across right under the lip, and then back thru the radiator support and under the battery tray to the starter relay.    I already had run the "batter direct" wires for my air conditioner there anyways and it is the shortest route and away from any heat of the engine. 

Regarding the ammeter.    Leaving it connected doesn't hurt anything as the huge bulk of the current is running thru the bypass wire.   However, it also will no longer be the least bit accurate.   So, i removed it and was able to replace it with a Voltmeter.   I believe it was a Sun voltmeter.    The wiring for it is from the two wires now connected together where the ammeter was, AND a separate wire to dash ground.   So now if i turn the key to Accessory, i can see what the battery voltage is...usually between 12.2 and 12.6.   Or turn it to ON without starting the car and i get about 11.5 volts as the Coil, ECU, Voltage regulator, and Choke heater all pull down its voltage.   Of course when the engine is started, and idling it will show about 12.5 volts for about 10-30 seconds before reaching and maintaining 13.5-14 volt.     Kinda neat !!

Thanks all for the input! This is the way I decided to run the cable. It makes sense to avoid heat and is really not noticeable. Ziptied to the radiator brackets and underneath the battery tray. I'll try to take care of the ammeter soon but it's good to know it won't bother anything

[CudaMoparRay]

Great thread, simplifying with pictures that are worth a thousand words. 

[71vert340]

  This bypass thread is great. I've read about it on several boards. I do have one question about it. Why couldn't a person just put a jumper wire between the two posts on the ammeter instead of disconnecting it entirely? Takes the load off the ammeter. The bypass wire shown installe in this thread takes the load off the harness connection and ammeter anyway. Just wondering.
Terry

[Poolshark314]

  This bypass thread is great. I've read about it on several boards. I do have one question about it. Why couldn't a person just put a jumper wire between the two posts on the ammeter instead of disconnecting it entirely? Takes the load off the ammeter. The bypass wire shown installe in this thread takes the load off the harness connection and ammeter anyway. Just wondering.
Terry

I think the point is that the ammeter is no longer accurate once you remove the bulk of the load from the harness connection, so the gauge will no longer be accurate anyway. It sounds like it is fine to leave it hooked up as is, but would no longer serve any useful purpose.

[crackedback]

Ammeters have grounded into the cluster housing.  Stuff happens.   I prefer nothing attached to them. 

Pick your method and go.

[Poolshark314]

Thank you once again everyone for the input! Updated the original post with steps and pics so hopefully this will help people in the future!

[dodj]

Ammeters have grounded into the cluster housing.  Stuff happens.   I prefer nothing attached to them. 

It doesn't do you any good connected anyway, why not remove them?

Disconnect the battery when messing with the ammeter wires.