Good Day,
I am needing to change out (not replace) my alternator when I go to one of the vendors' bracketry system for the alternator, power steering and a/c units. I have a couple of concerns regarding the alternator and the a/c unit. The alternator on my '99 is a Valeo unit with the VR attached to the back of the case. Of particular concern is (based on what I have read) that the alternator converses with the BCM and if they don't shake hands properly, a fault code would/could get thrown thus being a problem for inspection time. I also read that a tuner could get it programmed to accept the non-OEM alternator by flashing process. My question, if I need to change my alternator in order to use their bracketry what alternator would you recommend, and can I bump the amps up to a 140ish without causing issues? Several of the vendors for the brackets I am thinking of (LSX, CVF, DD, ICT) have advised me to purchase this Powermaster 160 Powermaster Alternator Wiring Harness Adapters | Summit Racing in order to make the alternator work properly with the BCM.

The power steering location on the unit bracketry causes no issues that I am aware of.

The A/C may need to be located to either the high or mid position on the passenger side depending on which vendor I go with. Some of the vendors recommend a Sanden unit and some say I can use my OEM unit so there is that. If I go the high mount route, I know I am restricted to the hood height since I don't want to damage the hood or anything else for that matter. Question is have any of you used any of these vendors for changing out your brackets and has anyone relocated the A/C unit from the low position to either the mid or high position? Thanks in advance and cheers!!!

 

First of all, the adapter cable in question merely adapts one type/brand of harness connector to a different type/brand of harness connector. It does no communication translation of any kind, nor should that be required so long as the alternator used is compatible with the vehicle.

EDIT: Increasing the output of the alternator should not be a problem. The only issue that I can potentially foresee is with a much heavier electrical load on the car, the engine may have a little trouble idling, especially when cold. I doubt that you will run into this, though at only 140A.

 

Thanks for the feedback, Tron Z. Just to be clear for me am I correct in that our alternator does communicate with the BCM (or ECM?) and if yes then if a non-OEM alternator is used doesn't it need to communicate? What I have been reading is that if the alternator cannot communicate with the BCM then a fault code will be thrown.

 

The alternator has two wires that go to the PCM, the red wire is 12v power from the PCM, the gray wire is a health or status wire that tells the PCM that the alternator output is within certain parameters, and will cause a charge fault if it is not. No real communication happens between the alternator and PCM or BCM.

 

The alternator has two leads that connect directly to the PCM (Powertrain Control Module) There is also one large and one small cable that connect directly from he alternator to the starter solenoid, via fusible links. There is no direct connection, nor communication between the alternator and the BCM. The two leads that go to the PCM are the F (Field) circuit and the L (exciter, or Light) circuit. Neither of these leads power the PCM. The PCM receives power from C2 pin 20 and C2 pin 61, as well as several ignition-controlled inputs.

On older cars the L wire went directly to the Generator light on the dash and effectively acted to enable / turn-on the alternator so that it would charge. On our C5s, the PCM controls alternator directly. The field circuit controls the amount of output from the alternator, so that the PCM can proactively control the idle speed of the engine, rather than passively react to the idle speed requirements. IIRC, this is a PWM signal, rather than a serial communications link of any kind.

Yes, the PCM monitors for both low system voltage and high system voltage, but no serial communication is necessary for the PCM to make those determinations / diagnostic decisions. If the PCM is unhappy with the response from the alternator as the field circuit is adjusted, the PCM asks the instrument cluster to illuminate the MIL via a serial comms message over the CAN bus.

I confess that I am more familiar with older GM alternator circuits, so I'm sure that someone will jump in to confirm, deny, or supplement my ramblings. lol

 

suggestion for you...look locally for an automotive electrical shop and have your stock alt rebuilt. DO NOT GIVE IT UP AS A CORE

 

Thanks to all. Yes, I am keeping my OEM and having it rebuilt. However, in the interim I guess what I was also asking was in the event my OEM does not work with the vendors bracketry can I just purchase another alternator like PowerMaster or another stronger Delco and use it safely? This the main concern I have because like I said earlier some of the vendors listed, I could use my OEM alternator with some spacers in order to get the alignment correct for the belt to travel. Has anyone use these brackets from either of these vendors?

Thanks...Al

 

I don't know anything about Powermaster, but yeah ... if the alternator is designed for use in your car, you can install it. You can't just install any random alternator, however and expect it to be compatible with your PCM. I have a RPO K63 110A alternator in my car (2003 Z06), but I see from the RPO list that a RPO KG3 145A alternator was an option for some C5s. If Powermaster (or someone else) has an equivalent replacement for the KG3, then it will probably work just fine in your car.