I am going to at least begin this mod today. I just received my 150amp breaker yesterday from Amazon, I'll still need to pick up an online fuse holder for the pcm as well.

 I do have a couple of quick questions.

 1. What size fuse for the PCM? I read both 7.5amp and 5amp. 

 2. I read that the ac noise would affect cruise control somehow on a manual truck. I haven't used my cruise much, just wondering how it affects this? Any other things it could mess with?

 I will take ac noise readings before and after to see how this works out and report back when finished. 

1 hour ago, Doubletrouble said:

1. What size fuse for the PCM? I read both 7.5amp and 5amp. 

 

5 amp. Over 100k miles never blown.

 

1 hour ago, Doubletrouble said:

2. I read that the ac noise would affect cruise control somehow on a manual truck. I haven't used my cruise much, just wondering how it affects this? Any other things it could mess with?

 

Anything with a inductive effect sensor. Cam sensor, crank sensor, output speed sensor, ABS sensors. Any inductive sensor creates a AC waveform when AC noise comes from the alternator it confuses any computer. 

Edited May 1, 20205 yr by Mopar1973Man

This show the voltage and amperage on the blue wire from the PCM to the alternator at idle with the headlights on with high beam, the heater fan on high speed, and radio playing; that's a 4.5 amp power draw.  If the load on the alternator load increase there is a chance the 5 amp fuse will blow so I sized mine to 7.5 amp.    

 

 

I first ran a 5 amp fuse. A few days later it popped. I then put a 7.5 amp fuse in. No problems for over 2 years. 

I used a 5 amp fuse and it hasn't blown yet but I do keep a selection of fuses in the truck anyway including 5 amp and 7.5amp

 I finished the ground mod. Not as bad as I thought it would be other than having big hands in small places. Ran the B+ alt through a 150amp breaker to the pass side battery. 

 Separated all the ground splices in the front of the engine just like in the thread.

 I checked my AC noise before I began (engine still cold, grids not cycling) and had .038-.040. when finished well......see the pic below.

 

Went for a short drive and the 150amp breaker popped. Not sure why

Got back to the house, shut it down and reset the breaker. Restarted, breaker popped again after a few minutes of idling. Reset while running and was fine for a 15 minute trip. Don't understand it.

15 hours ago, Doubletrouble said:

 

8 hours ago, Doubletrouble said:

 I finished the ground mod. Not as bad as I thought it would be other than having big hands in small places. Ran the B+ alt through a 150amp breaker to the pass side battery. 

 Separated all the ground splices in the front of the engine just like in the thread.

 I checked my AC noise before I began (engine still cold, grids not cycling) and had .038-.040. when finished well......see the pic below.

 

Went for a short drive and the 150amp breaker popped. Not sure why

adings before and after to see how this works out and report back when finished. 

mine went from a .035 to a .010 after the mod on 5 year old AZ alternator.

Edited May 2, 20205 yr by dripley

 I'm going to try to figure out why the break popped in the morning. Maybe the grids are pulling to much? Not sure if they were cycling when it tripped but I don't know what else could do it.

If the circuit breaker is popping its the grid heater solenoid sticking. Just got done with this in March for my landlord.

 @Mopar1973Man Is there a way I can test this? Where is it located? I don't want the breaker tripping Everytime I cold start the truck. The weather isn't real cold here lately but I guess it's cool enough for it to call for the grid heaters to come on.

Grid heater will be called if the air temp is 60F. It checks both battery temp and IAT sensor.

@DoubletroubleDisconnect the power from the driver's side battery to the grid heater relay then start it up and see if your breaker pops.  You should be able to follow the cable from the battery down to the relays right down by the driver's side battery... at least that's where they are on my 99.

 Thanks. I'll take a look in the morning.

Unhooked the power cable going to the grid heaters this morning and no problem. Breaker did not pop. Would it be a good idea to clean the terminals on the relays or should I just replace them? 

 Also, it should be fine to leave them unhooked for now since the temps are up?

mine have been disconnected now for about 9 months all through the winter BUT I will add winters in the UK aren't or shouldn't be that cold in general compared to USA, seen maybe -6C as the coldest this last winter, truck started fine, tucked the cables underneath the battery hold down so If needed it's a quick reconnect and alls good

I wouldn't mess around, I would just replace them.  I've seen pictures of what happens when they stick closed.  Your truck goes into "meltdown" mode.

 

I think I saw on here that leaving them unhooked will trip a check engine light but if you're ok with that then leave them unhooked.  I think @IBMobile has an article on how to do a switch for them that won't trip the CEL.  That's what I plan on doing to my truck.

Mine have been disconnected from the battery for 3 or 4 years now. It has not tripped a code yet. Pretty that works for all. If you disconnect the relays them I believe thats how the code gets set.

2 hours ago, dripley said:

Mine have been disconnected from the battery for 3 or 4 years now. It has not tripped a code yet. Pretty that works for all. If you disconnect the relays them I believe thats how the code gets set.

I'd second that, mine has not set any code relating to the heaters and they are disconnected from the battery

3 hours ago, dripley said:

Mine have been disconnected from the battery for 3 or 4 years now. It has not tripped a code yet. Pretty that works for all. If you disconnect the relays them I believe thats how the code gets set.

 

1 hour ago, wil440 said:

I'd second that, mine has not set any code relating to the heaters and they are disconnected from the battery

Awesome.  Good to know.  Our current weather here is high 50's to 60's so somewhat cool enough to trigger the grid heaters but not really needed.  Might just disconnect them till winter. 

I live in Cali and my grid heaters deleted. I only throw a code in the winter with hard starts. Other than that it doesn't show up. You should be fine