MCS 2000 Radio Mute Acting Strange

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Road Runner
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MCS 2000 Radio Mute Acting Strange

Post by Road Runner »

Hello everyone. I am requesting help troubleshooting my UHF MCS2000. The unit is remote mounted in a 2010 Dodge Charger with police pkg. The problem is when I PTT, the car stereo will not mute. I'm not sure what the deal is. I believe that I have the wiring correct, but I am getting some strange voltage numbers. I'm hoping that someone else reading this thread will be able to quickly identify the problem.

My setup is as follows:

- Remote mounted radio in the trunk
- Radio head (Model III) mounted in center console
- Motorola remote-mount kit including external speaker (mounted under passenger seat)
- Relay to convert ground signal on Pin 8 to 12v+ (stereo mute on the police package requires +12v to activate)
- Car battery is in trunk

The relay is 4 terminal SPST. As wired, it gets power from pin 14 on 2 of the terminals (one to provide + for the switch and one to provide +12v which is fed up a wire to the center console). Ground is supposed to come from Pin 8. When PTT, what should happen is the switch is closed and the power from pin 14 flows thru to the radio mute. But that is not what happens. I only get about 2-3 volts. Note that the installation manual for the radio even advises getting the 2 power and 1 ground connections from the radio, so from what I can tell this is as-intended by Moto.

I have tested the stereo mute function manually by applying 12V from one of the accessories under the center console and it works as it should. I've also tried running 12V from the radio in the trunk to the stereo mute wire under the center console (off pin 14, constant on 12V when radio is on), and this also works (but of course it mutes the stereo constantly when the MCS 2000 is on).

I have tested all the posts on the relay with a voltmeter using various configurations to verify ground or power at each terminal that should have it, and it all seems to work correctly. So, I don't believe the problem is with the relay (I've also swapped out the relay just in case). When I manually try and trip the relay by applying power and ground directly from the battery, it correctly flips the switch inside the relay, so I am sure it's not the problem.

I ran some other voltage tests with a voltmeter. Results here (all tested with voltmeter):

> 1. Neg lead on voltmeter to battery - terminal; Pos lead to relay output (supposed to provide +12v); result is +24-29 volts when PTT
> 2. Neg lead to battery - ; Pos lead to Pin 14 on radio; Result is +12.5 volts with radio turned on and NOT pressing PTT
> 3. Same as #2 except when pressing PTT, the voltmeter fluctuates between 25-45 volts! (what the heck!?)
> 4. Neg lead on voltmeter to Pin 8; Positive lead on voltmeter to Pin 14; Result is 7.9-8 volts with radio in standby; jumps to 27 volts when PTT

I can't figure out why the "sum of the parts" doesn't work, but each individual section seems to work. It's as if something is not kosher when PTT. The install manual says that pin 8 is supposed to go to ground when PTT, but whatever it is doing, the setup is not passing +12v no matter what I've tried.

Based on my testing, I have to wonder if there is something wrong with the ground connection on Pin 8. That seems like it's the problem, but I don't know why or if this whole scenario is normal. I know the stereo mute function in the car works (confirmed/tested), the relay works (also confirmed/tested), the wiring is good (confirmed/tested; note I have also checked for ground fault on the wire from trunk to center console and could not detect any), pin 14 outputs +12.5v or more (higher when car is running). Pin 8 seems to be the oddball.

I have searched this board (and others) but have not found this same situation described. I did find one other post on BatLabs where someone indicated MCS 2000 "AA" radios cannot have the accessory pins programmed. This particular radio has a "AA" in the middle of the serial number. However, I presumed that post meant the programmable pins, which in my case I am not using.

I've checked for all the "DOH" mistakes such as wiring the pins on the acc plug incorrectly, but all seems good. I have even tried a new accessory plug, but it's no help.

The radio IS programmed for radio mute. Also, power to the radio +12v is directly from the battery stud (not the terminal... instructions from Dodge on the PD package say not to do this and Dodge provides a tap about 1 foot from the battery which feeds directly off the pos terminal). Negative is run directly to the ground stud next to the battery, which is the closest ground to the radio (and again following Dodge protocol).

My thoughts atm:

- Is it possible programming is not fully setup for radio mute? If it needs to be set in more than one place, perhaps the programmer missed a spot?
- Could it be something to do with the Charger's electrical system? I have to admit that is my only complaint about this car with the PD package. It seems to have some odd behavior at times with regard to the electronics. I'm wondering if this radio problem could be related to how the radio is grounded and/or receiving power versus how the PD connector in the passenger compartment is grounded/powered.
- is there something wrong with Pin 8 on this radio?
- Should I just stop tinkering with car electronics (i.e am I being a moron here somehow?)

Any thoughts will be greatly appreciated! Thanks. :)
Road Runner
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Re: MCS 2000 Radio Mute Acting Strange

Post by Road Runner »

Any ideas? My bet is the ground from the radio on Pin 14 is bad, but I can't see how to confirm or how to fix it. Any suggestions?
KE7JFF
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Re: MCS 2000 Radio Mute Acting Strange

Post by KE7JFF »

Having dealt with Mopar electrical systems of various generations, I don't think thats the issue. I think the issue is something physical with the MCS2000 unit in particular; I would see about switching it out with another radio at this point and check then.
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Batwings21
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Re: MCS 2000 Radio Mute Acting Strange

Post by Batwings21 »

PLEASE tell me you have a relay with a diode built in, or you put a protection diode across the mute relay. If not you may have smoked the MCS.
Road Runner
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Re: MCS 2000 Radio Mute Acting Strange

Post by Road Runner »

Batwings21 wrote:PLEASE tell me you have a relay with a diode built in, or you put a protection diode across the mute relay. If not you may have smoked the MCS.
No, did not. But the relay has the following connections:

1. +12.5v input from MCS pin 14 (power to the switch)
2. +12.5 output to Dodge/Mopar PTIM (signal to mute stereo)
3. Ground from MCS pin 8 (ground for the switch, only when PTT)
4. +12.5v input from MCS pin 14 (power input to be sent to the PTIM in the vehicle)

Note that I can use the radio. It seems to work just fine. It just won't mute the stereo. For whatever reason there seems to be something funky with the pull to ground from pin 8. I have seen something like this before on these vehicles and the problem turned out to be that the power and ground were not on exactly the same part of the vehicle. For example, pulling power via some circuit and ground directly from the chassis. That seems ludicrous, but it made a difference in one instance. When the ground was pulled from the same circuit where the power was coming from, the voltage was correct.

Now, in my case right now, I can't see how that is the cause because both power and ground I'm taking from the radio. It seems like pulling pin 8 to ground on PTT is not quite right. And here is where we get into the limits of my electrical 12v knowledge (doesn't take long!)... is there a "ground hi" and a "ground lo"?? If so, what is the difference? Could the wrong one cause this type of odd problem?

Thanks to everyone replying, btw. :)
thebigphish
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Re: MCS 2000 Radio Mute Acting Strange

Post by thebigphish »

Can you confirm that the pin 8 does infact go to ground on PTT w/o any other radio hookups made?
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Road Runner
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Re: MCS 2000 Radio Mute Acting Strange

Post by Road Runner »

Sorry for slow response on my part. I'll try to find time to test just pin 8 this weekend.

In the meantime, I noted that in this post: http://batboard.batlabs.com/viewtopic.p ... 06&start=1 the author mentions programming the radio on F2, F3, F9, etc. for radio mute. I don't have any idea what he/she means by these "F" buttons. I tried pressing those buttons on the PC while programming a MCS 2000 radio using the latest CPS for this radio (02.02) and it did nothing. I don't see anything on either a Type II or III control either (plus the fact the buttons are configurable in CPS to begin with).

Would someone please enlighten me on how to get to these "F" functions and where they are? (e.g. CPS, the radio control head itself, etc.)?
KE7JFF
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Re: MCS 2000 Radio Mute Acting Strange

Post by KE7JFF »

Road Runner wrote:Sorry for slow response on my part. I'll try to find time to test just pin 8 this weekend.

In the meantime, I noted that in this post: http://batboard.batlabs.com/viewtopic.p ... 06&start=1 the author mentions programming the radio on F2, F3, F9, etc. for radio mute. I don't have any idea what he/she means by these "F" buttons. I tried pressing those buttons on the PC while programming a MCS 2000 radio using the latest CPS for this radio (02.02) and it did nothing. I don't see anything on either a Type II or III control either (plus the fact the buttons are configurable in CPS to begin with).

Would someone please enlighten me on how to get to these "F" functions and where they are? (e.g. CPS, the radio control head itself, etc.)?
In that post, he's talking about those options in RSS, not CPS as the person asking was using RSS instead.
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Road Runner
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Re: MCS 2000 Radio Mute Acting Strange

Post by Road Runner »

Ok. I only found one place in CPS to enable Radio Mute, and that flag is set. I was attempting to determine if my problem with it not working might be related to a setting in CPS. Thanks.
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