Strange electrical problem on the ST-R

bradc

1 AYC Bar
Location
New Zealand
First Name
Brad
Drive
Facelift Manual 400hp VR-4 Legnum
Ever since I've had the ST-R it has done something a bit strange, every so often for no real reason when touching the brake pedal the stereo would simply restart itself, almost as if it had a reset button like on a computer, the sound stops and the screen turns black, then it shows the welcome screen and the music starts playing again.

It has nothing to do with g-forces of actually applying the brakes, it would restart the exact moment the brake pedal was pressed down enough to turn the brake lights on.

It does it at random, sometimes not at all for seemingly months and then sometimes it does it every single time in a journey. I drove about 1300km's this weekend and sometimes it did it and other times it didn't. I don't beleive it restarted at all in the first 550km of driving, but seemed to do it quite a bit in the last journey from Lower Hutt to my house.

Something very strange happened though to me. When I turned the foglights on twice as it started to rain, the entire car felt like it had very quickly restarted, there was a bit of a jolt (loss of power) and the warning lights on the dash all came up as if I had just started the car. Over the course of a few seconds they all turned off as they normally do.

What I noticed for the first time is that when I apply the brakes and the brake lights are turned on, the odometer display, the fog light indication light and clock all dim slightly. This is sometimes accompanied by the radio switching off, other times it isn't. But the lights mentioned above always dim when I touch the brakes.

I have checked the alternator's output and it is a steady 14.30v at 700rpm, so it would appear to be healthy.

I also noticed that when I indicate (either left or right) the odometer, fog light indication light and clock also dim slightly, but this is not enough to restart the radio.


I therefore beleive that the most likely problem is that the stereo is simply wired incorrectly and that it is pulling power from the circuit that powers all of the above components and that the drop in voltage caused by the sudden increase in power when the brake lights are activated is enough to upset the stereo so that it restarts.

The only other options I could think of is that perhaps a relay is on it's way out, or perhaps the fuse that powers the loop is rated a bit low and is causing a voltage drop, but fuses aren't really designed to work that way!

Does anyone have any ideas before I try and get the stereo rewired?
 

king_panther

Gettin' tanked
Location
New South Wales
First Name
Brad
Drive
2012 VW Caddy 1.6TDI 7-Speed DSG. Still crappy DSG.....
Haven't you already made a thread about this before Brad?

I remember reading about this very issue earlier. I thought it got fixed?
 

bradc

1 AYC Bar
Location
New Zealand
First Name
Brad
Drive
Facelift Manual 400hp VR-4 Legnum
I have posted a thread when the stereo was just restarting, at the time I thought it was dodgy wiring and it didn't do it for quite some time after that thread.

But now I have new information regarding the lights dimming slightly.
 

unclepaulie

hellatemplate ;)
Lifetime Member
Location
QLD
First Name
Paul
Drive
hairdresser spec lancer coupe
dodgey wiring somewhere that shorts out. maybe helped out by fluxuating temperatures, makes it expand and contract?

everything earthed properly? maybe throw in an earth kit to see if it helps or hinders
 
G

Guest

Unregistered
Sounds like an earthing problem. Or maybe the regulator in the alternator is poked. I am unsure on your radio but from what i remember the engine ecu needs at least 9-10volts to work. people that stick batteries in the boot suffer alot from same soughts of problems when starting as the voltage drop over just thatt 4m length drains enough power when cranking t stop the ecu turning on. The more i think about it the more i think it is your regulator. as soon as the load comes on for the brake lights the regulator is not steping up the current required for the rest of the car
 

bradc

1 AYC Bar
Location
New Zealand
First Name
Brad
Drive
Facelift Manual 400hp VR-4 Legnum
I really don't think it is shorting out, if so it wouldn't dim the lights all of the time and only reset the stereo some of the time. I think it might have something to do with the stereo being cranked at the time, I didn't think to check how the volume affected things until after I got home today.

I think running another earth from the stereo and running a dedicated power cable to the stereo might be the best idea at the moment.
 

bradc

1 AYC Bar
Location
New Zealand
First Name
Brad
Drive
Facelift Manual 400hp VR-4 Legnum
Nathan, I will check when there is someone over here and see if the voltage changes at all when the brake pedal is touched.
 
G

Guest

Unregistered
I will have a look on mine to see if they are internal or external regulators. if they are external they are a piece of piss to replace.
Just reading what you said abot the fog lights causing dash lights to come on sounds like it is unable to stand the sudden power surge of the lights coming on. The cheapest thing to try first would be to sand the battery terminals and also the inside of the battery clamps. Double check the engine bay earths and do the same clean up to them. Eliminate all the bascs to start with
 

jet150

Anyone thirsty?
Premium Member
Location
victoria
First Name
Rob
Drive
VR4
yeah sounds like it could be the reg on the altenator. The brush's could be worn and not making enough contact on the shaft or it could be a dodgy diode on the stator.

Check the altenator first then check for earthing fault or wiring fault under the carpet or dash.
 

Peter_D

Leaving Skid Marks
Location
QLD
First Name
Pete
Drive
Cab Colt & Evo 6
Had a similar issue with the Evo turned out to be the battery terminal clamps where stuffed and losing connectivity on rough roads and when applying the brakes. Changed out the clamps and has never happened again.
 

snickells

Leaving Skid Marks
Lifetime Member
Location
Australia
First Name
Anon
Drive
Car
Everything I could think of has been covered Brad. Battery, Earthing, dodgy stereo install.
 

Kenneth

1 AYC Bar
Location
New Zealand
First Name
Kenneth
Drive
1999 Galant VR-4
I had this problem when I hadn't done up the battery earth terminal properly. Which is, as others have already suggested, a dodgy earth.

Make sure the stereo also isn't earthed through a wire it shouldn't, or the aerial.
 

Kristian

Leaving Skid Marks
Location
SA
First Name
Kristian
Drive
Changes daily
Yeah I was going to go with earthing too. Never did it for me while I used it Brad, maybe I wasn't driving it hard enough - bear in mind it was me who put that last battery in, I wouldn't trust my workmanship haha
 

bradc

1 AYC Bar
Location
New Zealand
First Name
Brad
Drive
Facelift Manual 400hp VR-4 Legnum
Thats the thing Kristian, it doesn't do it for a long period of time sometimes, and then it does it every time you touch the brakes for a little while!

I've checked the terminals and they are definitely on tightly. I'll try re-grounding and re-powering the stereo and see what happens.
 

Scottie

1 AYC Bar
Location
Victoria
First Name
Scott
Drive
1999 Type S Legnum
Does it do it when the engine is off? Try hitting the brakes a heap of times in the driveway and see if it does it. Maybe there is a wire hanging behind the brake pedal and the throw of the pedal itself is shorting/pulling a wire.
 

bradc

1 AYC Bar
Location
New Zealand
First Name
Brad
Drive
Facelift Manual 400hp VR-4 Legnum
I just tried it then with the engine on and off and nothing was dimming at all. Maybe it is a wire that is a bit loose.

I'll re-run grounds and power lines and see what happens.
 

wookie

Crunching Gears
Premium Member
Location
vic
First Name
Aaron
Drive
LTD and 1300 coupe
Bras, had a similar issue with mine yesterday. Been driving around town here in 35 degree heat. Had it sitting at shops idling for 10 mins waiting for my daughter and when we drove off, a minute later the radio restarted itself and i noticed a split second of power loss, then back to normal. Did it 3 times on the way home. Even noticed the volt guage on the a pillar dropped to zip when the radio restarted and the volt guage is wired independant of everything else. Got home popped the lid and the heatwave was massive. Checked terminals etc and no probs and hasn't done it since(cooler weather perhaps)...
Wondered if these cars suffered with heatsoak of some sort maybe affecting things????
 
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