dave110

OK, I'll be the one. What are we pondering there? A pegged gauge and what else. And that's not your truck or it wouldn't have Interstate battery and one of those messy red felt thingys under the post .

One thing that has always baffled me. My Chrysler 300M with 3.5L engine, 1 battery and modest electrical load gets a 130A alternator. My 99 Dodge Cummins with 5.9L engine, 2 batteries to charge, and nearly 200A of grid heater load alone gets a 136A alternator . Why it worked from new and now it doesn't is something I would like to know as well, but our stock alternators do seem quite a bit weak for the work they need to do. Maybe when everything was new it was just so enough amperage output to work OK, but now that things, whatever those things may be got aged and weaker it's just not enough and the poor alt. has to work too hard. In the AC world everything is sized 20% larger by NEC code to allow a little cushion. But here we're sized smaller for some reason. Cost? I mean if you wanted to buy a generator for your house and figured you have an 7800W load you would not buy an 8000W generator right? Common sense would say go with a 10,000W so it don't have to work at full capacity. I know the grids are a momentary load, but that moment gets pretty long when it's cold. So back to the OP's question. Wouldn't a larger amp. alternator be the way to go?

Good to know. The one in question is in the rear door. Once it warms up a little I'll have to pull it out and look a little closer.

Now twist it around some more yet. Why did my PSD go through only 1 alternator in 14 years? Only replaced because it quit charging. Dropped a Napa in and back on the road. Did not check for AC noise. Never even heard of it until I got this Dodge Cummins. Never an electronic issue. And those glow plugs draw alot of amps too. Take my 2002 300M. Original alternator and never an issue. My 03 Tahoe same thing. Original alt. and zero issues. But yet I check AC noise on this truck as much as I do tire pressure because on the issues they have. Don't crucify me for calling out Dodge Cummins here. I like my truck. But it seems like they have most of the AC noise problems. Now those who drink the blue Koolaid will say they all have the same trouble yada, yada, yada. Really? I have owned all of the big 3 and have only had this issue with 1, although I'm sure all have had an issue to some extent. I only bring this up to think outside the box. What's different with these trucks? Like @notlimah said the grid heaters are all I can think of. A rebuilt alternator for a Chevy is the same Chinese junk as a rebuilt for a Dodge and yet the Chevy has little if any issues with it that I'm aware of. Just thinking aloud. I'm going to keep my grids on a switch and only use when necessary. That's the best I can think of right now. The whole thing just baffles me.

Thanks for the reply. I'll see if I can dig up another speaker to try.

One of my rear speakers quit working. Before I condemn it I would like to make sure it is not something else. I put my meter across the 2 wires and got about .5V. Part of me thinks it should be 12V and part thinks speaker voltage is variable and increases with volume. Which part of me is right? Or am I all wrong?

Interesting. My 99 has front ABS. Was it an option that year @bigfish95971? The sensors live in under the inboard rotors so you need to pull the unit bearings to change them. What a PITA. I'm jealous of your 99.

Thanks You! My spare ECM is from a 99 truck so it would be plug & play if I ever need it. I may look for a newer model now that I know it's possible to use.

Glad you got it figured out. I have heard Bob say that before about the early ECM's and that explains to me why the majority of ECM failures I read about are on early model trucks. Was Bob saying that an 01 ECM could be flashed to work on a 98.5-99 truck?

I'm wondering the same thing. Very interesting article, but in reality %98 of us don't have the equipment or knowledge to 'build' our own alternator. My brand new Bosch still puts out .04 with everything turned on. I hoped for better but it's better than anything else I tried. When the grids hit it jumps to .09. I still say the best way to save the alt. is to turn those grids off unless they are really needed. Unless there is an alt. readily available that will handle the load that is.

Interesting. I was under the impression that the battery temp. sensor had more to do with grid cycle than IAT and coolant temp.

I could not agree more that the grids are hard on the alternator and AC noise output. That's why I put them on a switch. It get too cold here to do without. I turn them on to start the truck, then simply turn them off once it's running.

^^ Not surprised. I've heard nothing but good about them.

I got my center cap replacements from Summit and they matched the original 99 assuming I had originals.

Flight systems is local to me here. We use them at work for our many Hyster forklift electronic repairs. I had checked the website a while back to see if they offer ECM repair and at that time I don't think they did. That was probably before they partnered with RAE. I'm glad to hear about this because Flight Systems seems to be a very good company that has given us great service over the years, and being only 2 hours away is nice too. Thanks for the update.

Well, I'm not sure what you're implying, but I did what I posted and it works fine. Only side effect is the 2 trouble codes which is not a deal breaker for me.

Just to update. I ran the relay ground wires to a switch in the cab. I tested it all last week while hunting. Close the switch to enable grids to start truck and once it's running open the switch to disable. Now till the end of the week my batteries were much happier because the grids were not stealing all the charge. I do get a code doing it this way but no CEL. Very happy I did it.

Your second suggestion is exactly what I'm talking about.. It would be no different than manually disconnecting. You'd just be able to do it with the flip of a switch. I would think any 200A or greater relay would do like golf cart relays are 300A. On another thought, why not switch the grounds on the original relays? That way there's no chance to damage ECM by a possible short to the power wires like mentioned above.

A little late to the party. I was thinking of disconnecting the grid leads from the battery, and putting a heavy duty relay like those found on golf carts or snow plow setups in between. Then run the trigger wire to a toggle so you don't have to pop the hood all the time. I'd like to disconnect my heater once the truck is running even in the winter since it more than doubles the AC noise output of my alternator once it cycles. I have a lot of short trips and it seems my batteries never get charged in the winter once the grid starts to cycle. And some of my trips I never get to 20MPH to stop the cycling. It's always in the winter when my TC hunting problems start and then go away in summer.

Anyone know of a source for Bosch diodes? I put a brand new Bosch on last year. Not a 'new re-man' but a brand new alternator. I was hoping Bosch would be a better option but it's already putting out .04 unloaded and .09 when the computer killing grids cycle. Might have to look in to a relay to turn them off once the truck starts so they don't cycle during warmup.

Takes a pretty stout pump to suck 15w-40 up from 3 feet below. I doubt any FASS would be up to the task .

Have not had to replace mine yet. Now Dad's 09 went at around 45k and I put a NAPA in. Dad's gone and sold the truck at 65k so I don't know how it held up.

Problem solved! I had those bolts about as tight as I could get them with 3 fingers on a 7/16 box wrench. After a few taps with a brass hammer I was surprised to get another 1/4 turn out of them. I suppose either the China bolt heads are not square to the threads or the crush washers are not parallel or too hard or something, but the tap trick worked. Now if only all my problems could be solved with a hit from a hammer...................

Dang! I was all ready to do an 02 caliper conversion . Off to the shop to bathe in DOT 3 again.

It's interesting you mention that @jlbayes. Mulling over it while trying to sleep I thought the same thing. One good whack with a brass hammer might seat the copper washers. It's the last thing I considered trying before taking it apart again. I wasn't sure it was a good idea, so I'm glad you suggested as well. I broke a banjo once before so I'm a little gun shy. I'm gonna go at it again shortly and I'll report back.