I recently installed 2 amps (JL Slash 500/1 and 300/4) that were previously installed in my old '04 z06 into my '10 Grand Sport and all was fine for a day before I started to get some whine (I think it's due to the HU being grounded into the factory harness with the amps being grounded at the battery in the trunk). I'm hoping I can get rid of this whine by running a ground from the HU to the amps alongside the remote turn-on wire (which I ran right up the transmission tunnel).

Today, the whine is the worst that it has been since I installed everything 3 days ago, and I further noticed that my AC was not blowing cold when sitting at stop lights, unless I turned the HU off.

I assumed that the electrical load was too large so the car's computer was selectively choosing which accessories to turn on/off; is that a safe assumption?

It was my understanding that the factory alternator should be just fine with 2 amps of this size, am I mistaken?

Could the ground issue be the cause of this? Or is there too much of an amp load for the factory alternator?

Thanks in advance!
Pat


(I cross-posted this into the Audio/electronics section as well but haven't gotten any response...)


Edit: Appears to be a coincidence in timing between the issue showing up and the amplifiers getting installed... The top plug to the fan control module appears to be scorched in the middle plug (the ground) which would cause the issue of the A/C condenser/compressor shutting off at idle (as it requires the fan to run at idle/low engine speeds) and the new issue detailed in post #3 of the car overheating when stationary.

Hopefully this post will help someone searching with similar symptoms in the future: check the wiring/plugs for the fan control module! Here are a few helpful threads/posts:
https://www.corvetteforum.com/forums...connector.html
https://www.corvetteforum.com/forums...connector.html
https://www.corvetteforum.com/forums...post1578797837

 

Not sure of the load you pulling with the amps(amperage of the two), but will bank that your causing electrical gremlins with the alternator not being able to keep up with the demand.

your pulling 90 amps with the two amps at max output, so it time to upgrade the alternator to a 6 pole billet alternator. The oem 3 pole alternator only puts out about 14amps at idle, while the billet will put out about 65amps at idle isntead.
Note, the system cranked with the car sitting at a light, and no alternator is going to be able to keep up with the draw on the battery. But with the billet alternator putting out about 65 amps at idle, and ramping up faster in output as the car is driving again, it will recharge the battery much faster that the OEM alternator. Also, 170 amps will be fine for the addition 90 amps that your pulling with the amps over the cars base needs.

As for the whine, it not coming from the main power into the amps, but from the radio to amp input signal wires isntead. Double check your radio adapter module if you are using the OEM head unit and you should be able to float the amp input signal grounds so they are not tied back into the chassis ground. Also, depending on the radio adapter, may have to install resistors as well.


Really, just need to know what alternator you have in the car, what spark plugs and wires, the draw amperage of the amps, and details on the radio and amp system (if stock unit with adapter or after market with adapter) and wiring you used.

 

New twist, car overheated at lunch... With the stereo off (bc of the A/C issue) I noticed the car temps raising to the point where it turned the A/C off on it's own. The car only kept the high temps when the car was sitting, and the temps would drop as soon as the car got moving.

Thinking it's an issue of the fans not turning on? Maybe the electrical connector to the fans burned up, as is known to happen? I'll see if the fans are kicking on on their own later on tonight or tomorrow.

As to the whine, I think it's only coming from the center dash speaker and the rear speakers (which are currently running off the headunit, though I'll be replacing them with some coaxials here shortly as i want them improved over the factory speakers but don't want to run no rears). I'm thinking that the whine will be gone once I disconnect those 3 speakers.

I have the factory alternator in the car, factory plugs/wires, the HU is the Sony XAV-AX100 with the PAC RP5-GM11 harness. Wiring is monster branded speaker wire, RCAs, and Power cables to distribution blocks for both power and ground, with 0/1 gauge running from those blocks directly to the optima yellow top battery in the trunk.

The RCA wires only come near the power wires when they plug into the amps.

 

Looks like it was just a coincidence that this issue showed up a few days after installing the amplifiers/sub/component speakers...


The top plug to the fan control module was a little bit scorched in the middle (ground) connection; this would explain both the overheat condition (95* and humid here in Houston will cause the coolant to heat up real quick when the car isn't moving) and the air conditioning issue as the compressor turns off when the car is idle and the fan isn't running.

Fun thing is that the fan started working again after plugging it back up (connection probably just re-established itself) but I still took the car in as I don't want to be in a bad spot when it cuts out again (i know it's an easy fix, but I figure I'd like to get the coolant flushed, which I don't have a fluid container large enough to do, so I'll just let my indy shop handle it).

I'll still be looking into upgrading the alternator though!

Thanks!