Pulsing Noise In Dash When Starting My R33

[JodieR33Chick]

I have an R33 GTS-T 4door ('94), and just recently when I start my car there is a noise coming from the dash or somewhere in that general area that sounds like a pulsing beat. It sounds as if something is trying to move or open and is getting stuck or held back by something. Kind of like the sound a pedestal fan makes when you try and stop it from oscillating. My friend, who dyno tunes ands works on alot of Skylines says its a common problem with them but he is not sure what it is.

Please help. If anyone knows what it is and how to fix it please let me know.

[Links]

Off the top of my head it sounds like the aircon vents are trying to open when you turn the car on.. Some other people might have more ideas, it's kinda common in older R33's..

[Gazee]

yea mine does the same thing, i've noticed when the the temp setting is below 25 it stops doing it.. i still don't know how to fix it tho.. but i dont think its something so dramatic... i could be wrong

[DECIM8]

R34 randomly does it .. It is the aircon as it does it more when the air con is on .. good fix is turning the cd player up over 10 or so

[JodieR33Chick]

Off the top of my head it sounds like the aircon vents are trying to open when you turn the car on.. Some other people might have more ideas, it's kinda common in older R33's..

Yeah thought it might have been something to do with the AC. Cheers

[JodieR33Chick]

R34 randomly does it .. It is the aircon as it does it more when the air con is on .. good fix is turning the cd player up over 10 or so

If I can't fix the problem, cranking the music sounds like my only option!!

[Links]

I think it's the motor trying to open the valves so that it can change where the hot/cold air is routed.. Only way to fix it is to pull the whole dash out and it's known to be alot of effort.. it's been in other threads..

Amusing what you find.. here is the site with photos on what it takes to remove it and get to it.. I believe it's the heater unit motor trying to open..

http://gtr.ferni.net/misc/dash_removal/

Links

[Baconer]

set it to recirculate and turn the unit off, fixed my problems and fixed my fuel economy

[JodieR33Chick]

I think it's the motor trying to open the valves so that it can change where the hot/cold air is routed.. Only way to fix it is to pull the whole dash out and it's known to be alot of effort.. it's been in other threads..

Amusing what you find.. here is the site with photos on what it takes to remove it and get to it.. I believe it's the heater unit motor trying to open..

http://gtr.ferni.net/misc/dash_removal/

Links

Well that certainly looks like a whole lot of fun to attemp!!! Think I'll get my friend with the expertise to give that a go for me. Thanks heaps for the info.

[tak]

my friend also have that problem...

anyone plz help!!

[The Sherrid]

well this pulseing noise in dash for me has been narrowed down to this. on two seperate skylines the exact same noise and exact same climate control actualor (motor) has been the culprit.

if you follow this link (same as above)

http://gtr.ferni.net/misc/dash_removal/

and enlarge the picture with the foot in it you can see a little black box ontop of the big white plastic thing (the heather core assembly unit). this little black box held in place by what looks like 3 screws is actually only 2 - just to help you identify it in the picture. what it does is it controls the opening and closing of the vents from head to legs and if it is jamed bysomething will make that noise.

the interseting thing is that on both skylines (both series 1) neither were jammed, in fact if i unscrewed the unit itself and had it resting in the palm of my hand it would still make the noise. so that eliminates anything jamming the vents open.

then i pulled the unit apart to see if any gears inside were sliping or broken. what i found was that no gears were broken and or slipping in fact the unit is functioning like it should. also the little arm that comes off the unit which slots into the heater core assembly will only move 90 degrees. so when the little motor inside turns the gears and inturn moves the arm, the actuall arm travel is limited by the case design not by the motor. which means that the little motor inside wants to keep turning like 2 full rotations but the plastic arm has a stopper built into the case that makes it stop at a the open or closed positions only. so this led me to look at what was controlling the little motor iside the case.

inside there is only a little motor and a resistor. so the circuitry controlling the motor must be inline somewhere. sure enough i stripped back the entire wiring loom to follow the 2 wires all the way back to the climate control unit and they go directly to it with no relays or anything else inbetween.

So logically it must be the climate controll unit that is the problem. Naturally i tried another then another a total of 4 different climate controll units and none stopped that little motor from turning to far.

so i went to some wild card ideas, took out anything that had been installed (not factory) i took out the stereo, the boos controller, then the turbo timer. still the same. I then made sure that all the earths were screwed in and tight. still no change. I then went on to change all relays, fuses and odd bits and pieces, all otrher modules associated with the heating and cooling, even the flasher can (i know the flasher can has nothing to do with this problem) still that noise was present.

i then noticed that when the mode was set to legs only and the car was turned off and then on again it made the noise.

then i noticed that even if i set the node to legs only then turned the climate control unit off then the car off and on again it still made the same noise. which indicated that the little unit was getting a stray signal or current through the climate control unit imediatly at start up.

so now i'm calling in my auto elec friend to help i'll write back when i find the problem.

[Eug]

did your auto electrician friend manage to solve the problem?

[Trent04]

hey feller's, yeah my skyline does it aswell lol it only goes for a few seconds and then just stops? its pretty annoying, but i just agree with DECIM8, i just crank the muzik lol but would like to get it fixed any help appreciated.

cheers fellers

[The Sherrid]

well this pulseing noise in dash for me has been narrowed down to this. on two seperate skylines the exact same noise and exact same climate control actualor (motor) has been the culprit.

if you follow this link (same as above)

http://gtr.ferni.net/misc/dash_removal/

and enlarge the picture with the foot in it you can see a little black box ontop of the big white plastic thing (the heather core assembly unit). this little black box held in place by what looks like 3 screws is actually only 2 - just to help you identify it in the picture. what it does is it controls the opening and closing of the vents from head to legs and if it is jamed bysomething will make that noise.

the interseting thing is that on both skylines (both series 1) neither were jammed, in fact if i unscrewed the unit itself and had it resting in the palm of my hand it would still make the noise. so that eliminates anything jamming the vents open.

then i pulled the unit apart to see if any gears inside were sliping or broken. what i found was that no gears were broken and or slipping in fact the unit is functioning like it should. also the little arm that comes off the unit which slots into the heater core assembly will only move 90 degrees. so when the little motor inside turns the gears and inturn moves the arm, the actuall arm travel is limited by the case design not by the motor. which means that the little motor inside wants to keep turning like 2 full rotations but the plastic arm has a stopper built into the case that makes it stop at a the open or closed positions only. so this led me to look at what was controlling the little motor iside the case.

inside there is only a little motor and a resistor. so the circuitry controlling the motor must be inline somewhere. sure enough i stripped back the entire wiring loom to follow the 2 wires all the way back to the climate control unit and they go directly to it with no relays or anything else inbetween.

So logically it must be the climate controll unit that is the problem. Naturally i tried another then another a total of 4 different climate controll units and none stopped that little motor from turning to far.

so i went to some wild card ideas, took out anything that had been installed (not factory) i took out the stereo, the boos controller, then the turbo timer. still the same. I then made sure that all the earths were screwed in and tight. still no change. I then went on to change all relays, fuses and odd bits and pieces, all otrher modules associated with the heating and cooling, even the flasher can (i know the flasher can has nothing to do with this problem) still that noise was present.

i then noticed that when the mode was set to legs only and the car was turned off and then on again it made the noise.

then i noticed that even if i set the node to legs only then turned the climate control unit off then the car off and on again it still made the same noise. which indicated that the little unit was getting a stray signal or current through the climate control unit imediatly at start up.

so now i'm calling in my auto elec friend to help i'll write back when i find the problem.

________________________________________________________________________________

_____________________

well i apologise for the delay but, it's better late than never.

What actually happens is the climate control unit actuates the motor.

when this happens the climate control unit is set to actuate the motor for a longer time period than it actually needs.

Sounds strange but i put it down to 2 things.

1. It's a programing fault in the climate control unit from factory

2. It's designed that way so as to keep the vent door open while another operation is completed or a combination of both

In either event, what happens is the motor reaches it's maximum travel and stay's jammed there while the motor keeps supplying force, After time, months years etc, the motors and it's gears inside eventually succumb to slippage and hence the click noise is the gears slipping.

this click noise stops when power is cut off to the motor from the climate control box.

Now it just depends on how your individual box copes with the strain, some will shit them solves early, some are louder than others and some are just a little tougher than others.

you have 2 options. (Both require a pulling out of the dash)

1. roam around from wrecker to wrecker and hope to find one for the right price and hope it's not already stuffed.

2. The SURE FIRE method is to with the dash out, watch the travel of the motor and stop it just short of it's full travel by screwing in a standard screw into the plastic heater surround in between the motor arm and the bit of plastic at the end of it's travel. In effect you are now just putting the load on a part of the gear system (in the box) that is not worn.

The best way to find this spot is to just hold the arm with your finger just before it fully closes.

of course, eventually this part of the gear system will wear under the strain too.

If you do it right you can still have the full motion of all the vents.