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OE Power antenna operation question

J

jmorrnsx

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5 November 2021
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I’m not sure if my question has been discussed in a previous thread, but I just had a question regarding the operation of the OE antenna, on a 91 NSX.
When the car is started or it’s in the accessory II position the antenna goes up, if I turn my radio off while the car is running, the antenna stays up,is this a normal operation or is there a way to put the antenna down when the car is running and the radio is off?
 
The same power to the speaker amps also triggers the antenna.

Smartenna is a device that checked for CD player and suppressed the antenna. Search on it.

You could use the 13P DIN for the cellphone to control the antenna with some relays or the smartenna.

I have a Smartenna for sale.
 
jmorrnsx said:
I’m not sure if my question has been discussed in a previous thread, but I just had a question regarding the operation of the OE antenna, on a 91 NSX.
When the car is started or it’s in the accessory II position the antenna goes up, if I turn my radio off while the car is running, the antenna stays up,is this a normal operation or is there a way to put the antenna down when the car is running and the radio is off?
Click to expand...
Normally, the antenna only goes up when the head unit is turned on. It should go down when you turn it off. In other words, with the car running and the head unit off, the antenna should be down. It sounds like someone did some re-wiring in your car making the antenna go up when the car is on or in the accessory II position despite the head unit being turned off.
 
I_M_Legend said:
Normally, the antenna only goes up when the head unit is turned on. It should go down when you turn it off. In other words, with the car running and the head unit off, the antenna should be down. It sounds like someone did some re-wiring in your car making the antenna go up when the car is on or in the accessory II position despite the head unit being turned off.
Click to expand...
Thank you for chiming in. When I purchased the vehicle, the power antenna motor was still connected but the mast portion was broken and they had one of those screw in rubber antennas so I replaced it with a whole brand new OE motor and mast assembly and it was installed by a technician at an Acura dealership. I’m assuming there’s only one way to connect these assemblies to the head unit.
 
As soon as there is power to the car with the key, the antenna goes up regardless if the radio was on or off. With the power on, and you shut off the radio antenna stays up.
 
Correct operation is as described in the previous posts. This is the schematic for the power antenna

Antenna.jpg

The antenna up signal comes over the pink/white wire that originates from the head unit. It is the same signal that switches the relay that controls the power amplifiers in the doors and footwell. That up signal should only occur when the head unit is switched on.

Disconnect the plug at the power antenna unit and find the pink / white wire in the body side wire harness (it matches to yel/wht on the antenna pigtail). With the ignition switch in the I position and the radio switched off, check for voltage on the pink/white wire. If you have 12 volts with the head unit switched off then somebody has messed with the wiring for the antenna control (check the wiring at the power amplifier relay for modifications) or the head unit has problems. If the signal on the pink/wht wire switches high / low with the head unit on / off then that would be an interesting problem.

My gut reaction is that Drew is correct and somebody has messed with the wiring associated with the amplifier relay / power antenna signal wiring. Only testing will tell.
 
Thank you @Old Guy for this information.
I have a copy of previous service records and one R/O shows the radio and floor amp were sent out and repaired in 2017. Maybe during reinstalling the radio and amp something obviously wasn’t done correctly. I’ll add this to my list of electrical issues.
 
You are making us guess and assume...

1. OEM stereo?
2. What other "electrical issues"?
3. Any non-OEM electrical equipment on vehicle?
 
Brake Warning lamp staying on in cluster likely means the cluster needs to be rebuilt. You need to attend to this ASAP, you can literally set your car on fire. At a minimum it will destroy your cluster and it gets expensive real quick. I'd disconnect your battery until you get this resolved, you can drive the car with the cluster completely disconnected.

For antenna issues: disconnect your radio, requires removal of center console which requires special information and a detailed work process. If antenna continues to go/up and down with the Key On/Key Off then you get to do additional diagnosis.
 
Thank you for the warning.
The light comes and goes.
This car had a history of a water leak in the trunk in the past. All the taillight gaskets were replaced in 2017. The trunk has a musty smell to it. I recently replaced the whole trunk liner with a new OE liner. I’m thinking this could be the issue with brake light out warning on.
 
There is a good possibility of wishful thinking on the brake indicator, It is not too difficult to bypass the warning system.

Brake lamp warning bypass... what am I doing wrong?

I've put a different LED high level brake light into my car as I don't have the factory rear wing, so this naturally means the Brake Lamp warning light on the dashboard comes on. I've done the bypass as per other posts on this site by connecting the white wire with green stripe to black wire...
www.nsxprime.com www.nsxprime.com

I recommend depinning and grounding the wire. as I don't like to damage OEM wiring.
 
There are two brake light sensor failure modules in the trunk - one associated with each light assembly. Bad electrical connections at each module or aging relays in the module could cause intermittent operation of the brake bulb failure warning light if you are applying the brakes. If the bulb failure warning light come on intermittently without application of the brakes I would be more inclined to look at the circuits on the instrument cluster. However, as noted in that post linked by Drew, the high mount LED brake light does work into the bulb failure monitoring circuit. Check for bad connections (broken wiring where it goes up into the trunk lid) because an intermittent connection can cause the bulb failure warning circuit to energize even without application of the brakes.

The 'cluster failure can cause the car to start on fire' is an often repeated theme; however, I only recall a single report of that occurring and it was anecdotal - not a report by the individual experiencing the fire. I think the much greater risk is that unchecked electrolyte leakage damages the circuit boards beyond simple repair leading to a bigger expenditure.

If you have had moisture in the trunk, disconnecting all the electrical connections to check for signs of corrosion at the bulb failure monitoring relays and the connection to the high mount brake light would never be a bad thing. This includes the grounding connections.

Do the voltage check on the pink/white antenna control wire in the trunk. Depending on what you measure that will indicate whether the problem is originating 'up front'. If the head unit was removed for repair, perhaps the repair involved the amp / antenna switching circuit with the 'fix' being permanently switched on.
 
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The cluster fires are not common, but they are a problem

gauge cluster fire issues

Todays work shedule: For my 2nd customer this year who came to me, cause his gauge cluster cought fire! Lucky I stock all parts. The 280kmh gauge was ordered in Japan last year in fall and I just got it 2 weeks ago. Also check out how many different check light versions are out there. Who...
www.nsxcb.co.uk

Speedo problem

Hi, My speedo is not working. Originally i thought it was the speed sensor on the transmission, the problem was once the car warm up the speedo just stop at 0km/hr. So when i start it up in the morning and drive it out it would work for about 5km then it stop working. It was like this for...
www.nsxcb.co.uk

Had one just last year in AU, an expensive fix.

What is interesting is that the fires seem to be limited to RHD cars and no LHD that I know of. This is strange because there is no effective difference between RHD and LHD clusters.
 
Good observation. Quite a few first hand accounts of cluster failures on Prime, particularly if you include the speedometer or tach going out of calibration. But, I do not recall any first hand accounts of cluster failure being tied to a vehicle fire.

I suspect less of an issue in Oz and NZ; but, based upon the pictures I see on NSXCB the British cars all look like they have been stored in a ziploc bag full of brine. The unpainted alloy components all look in really rough shape which has me wondering how much solder bloom is present on all those circuit boards even with conformal coating and what the tinned terminal connections look like.

There are certain advantages to living in what qualifies as dessert like conditions!
 
Just wanted to thank everyone for contributing to this post, all your help is greatly appreciated!!
I will get to the bottom of these issues and let you know what the outcome will be.
Just one last question.
Does anyone know a very good Nsx Tech in the Toronto Ont. Canada area?
I have my very good Acura dealership for the “just in cases”.
 
NSX service: Rob Magro 905 483-6247
PM'd you on a general electrical wizzard.

Side note: Look for a manual over-ride switch for the power antenna. Mine was added to the emergency trunk release.
 

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