Neutral Safety Switch Questions
02-10-2009, 07:03 AM
#1
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Neutral Safety Switch Questions Can the Neutral safety switch (bolted to the transmission on the driver side) be deleted without any adverse affects? I know my prior LT1 4L60E didn't have one one it, and I'm looking to clean up things a bit.
It looks like this.
It looks like this.
02-10-2009, 07:55 AM
#2
I have that plug on the harness out of the 05 Hummer I am using.
It appears that:
wire 1 is the clutch start sw signal.
wire 7 is grnd.
wire 9 is the park/neutral signal.
wire 10 is backup lite power.
wire[s] 11&12 are ign voltage.
In looking at the schematics, it would indicate to me that if the sw is eliminated, then the start relay is going to be inop, and the starter won't engage..[??]
I see U R looking at a T-56. Maybe look at that wiring too, and see if you could do something until the trans is changed??
My combo is going in a 55 Chevy, so I'm going to eliminate that sw/harness, etc, and use the oem, column mtd N/S sw...
It appears that:
wire 1 is the clutch start sw signal.
wire 7 is grnd.
wire 9 is the park/neutral signal.
wire 10 is backup lite power.
wire[s] 11&12 are ign voltage.
In looking at the schematics, it would indicate to me that if the sw is eliminated, then the start relay is going to be inop, and the starter won't engage..[??]
I see U R looking at a T-56. Maybe look at that wiring too, and see if you could do something until the trans is changed??
My combo is going in a 55 Chevy, so I'm going to eliminate that sw/harness, etc, and use the oem, column mtd N/S sw...
02-10-2009, 03:33 PM
#3
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Well my car has a column mounted neutral safety switch, and the starter wire runs from a relay in the "convenience center". This is in reference to keeping the 4L60E. Reverse lights power, neutral safety switch, and what looks to be everything else associated with this plug seems to be mounted on my column. The Transmission Range switch Signals all go to the PCM, and I'm wondering if they are even needed.
1
GY/BU
275
Park Neutral Position Switch Park Signal
2
--
--
Not Used
3
YE
1479
A/T Neutral Signal
4
YE/RD
772
Transmission Range Switch Signal B
5
BU/WH
771
Transmission Range Switch Signal A
6
GY
773
Transmission Range Switch Signal C
7
BK/RD
450
Ground
8
WH
776
Transmission Range Switch Signal P
9
--
--
Not Used
10
L-GN
24
Backup Lamp Supply Voltage
11
BN/BU
239
Ignition 1 Voltage
12
GY
434
Neutral Safety Switch Signal
1
GY/BU
275
Park Neutral Position Switch Park Signal
2
--
--
Not Used
3
YE
1479
A/T Neutral Signal
4
YE/RD
772
Transmission Range Switch Signal B
5
BU/WH
771
Transmission Range Switch Signal A
6
GY
773
Transmission Range Switch Signal C
7
BK/RD
450
Ground
8
WH
776
Transmission Range Switch Signal P
9
--
--
Not Used
10
L-GN
24
Backup Lamp Supply Voltage
11
BN/BU
239
Ignition 1 Voltage
12
GY
434
Neutral Safety Switch Signal
02-10-2009, 06:55 PM
#4
I don't have my 4l60e tranny nuetral safety switch installed & the wire from the harness, of course, is not connected. It starts and runs fine. I will say...I defineately will be installing everything in the future though. I have started it in gear, and thats not too safe. Also, I have turned the engine off with the tranny in gear, left the key in the ignition in the "on" position, and burned out my fuel pump & fuel pump relay, etc. Also not safe. I thought I could get used to not having a safety switch wired in, as I have always driven stick-shift cars. But, It's better to have a switch on an auto.
02-10-2009, 08:46 PM
#5
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Well with the neutral safety switch on my column, I can't turn the Key to "start" with the car in gear, so that alleviates that problem. I've driven a mix of autos and sticks, so the only problem I see could be what you mentioned about the fuel pump relay and the fuel pump. Any other opinions?
01-02-2010, 08:13 PM
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I'm reworking my harness and lost quite a few wires that the 'how to" on lt1swap.com said I didn't need.
My harness is an 04 and the only wires left on the larger connector is a pink and black.
I guess my question is what wires would I actually need? Is there anything going to the P/N switch that controls PCM functions?
My harness is an 04 and the only wires left on the larger connector is a pink and black.
I guess my question is what wires would I actually need? Is there anything going to the P/N switch that controls PCM functions?
01-03-2010, 11:30 AM
#7
The PCM only needs to see if the vehicle is in Gear or P/N for idle control. There is a setting in HPtuners for whether the vehicle has a P/N or PRNDL switch. The starter neutral safety switch and reverse lights switch already on the vehicle can still be used to control those functions.
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01-03-2010, 11:47 AM
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The PCM only needs to see if the vehicle is in Gear or P/N for idle control. There is a setting in HPtuners for whether the vehicle has a P/N or PRNDL switch. The starter neutral safety switch and reverse lights switch already on the vehicle can still be used to control those functions.
01-03-2010, 05:29 PM
#10
If you don't hook up the wiring on the selector switch, it will not work at all
01-03-2010, 06:24 PM
#11
That setting in the PCM only relates to what type of display the vehicle has. If you set it to none and the vehicle has a display, it will not send the signal up the class 2 data buss to operate it. If you set it to Park / Nuetral and you have the full display only park and nuetral will light up. It doesn't mater where you set it, if you don't have a display
If you don't hook up the wiring on the selector switch, it will not work at all
If you don't hook up the wiring on the selector switch, it will not work at all
01-04-2010, 06:55 AM
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So I guess I still need to use the big plug
01-04-2010, 07:01 AM
#14
Here is something I found while researching this same question
The PCM uses the signal to adjust idle speed based on whether the car is in gear or in park/neutral.
As soon as the PCM "sees" the car go in gear it drops the idle speed by around 100 rpm to prevent jerking going into gear, and to prevent tugging at the torque converter.
It can be considered as optional on a swap. As long as the line is left open the PCM will always assume the car is in gear, and will drop to lower rpm when the engine is started. This also causes a much quicker rpm rampdown on a cold engine start.
Some aftermarket wiring harness companies that have no clue as to how the PCM works will wire this line to ground which makes the PCM think the car is always in park or neutral. On some applications this allows some diagnostic tests to be skipped (EGR, purge, etc.) so that these items can be left off without setting a code. The problem is that the idle is too fast then, and the car wantts to pull a little when sitting still, as well as other issues.
The PCM uses the signal to adjust idle speed based on whether the car is in gear or in park/neutral.
As soon as the PCM "sees" the car go in gear it drops the idle speed by around 100 rpm to prevent jerking going into gear, and to prevent tugging at the torque converter.
It can be considered as optional on a swap. As long as the line is left open the PCM will always assume the car is in gear, and will drop to lower rpm when the engine is started. This also causes a much quicker rpm rampdown on a cold engine start.
Some aftermarket wiring harness companies that have no clue as to how the PCM works will wire this line to ground which makes the PCM think the car is always in park or neutral. On some applications this allows some diagnostic tests to be skipped (EGR, purge, etc.) so that these items can be left off without setting a code. The problem is that the idle is too fast then, and the car wantts to pull a little when sitting still, as well as other issues.
01-04-2010, 09:22 AM
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Anyone know if the neutral safety switch plug is interwoven in the stock engine harnesses for the PCM or is it connectted through one of the connectors like the C100?
01-04-2010, 10:59 AM
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neutral safety switch I want to use the neutral switch in my 6 speed transmission. Does anyone have a wiring diagram on how to wire it in and what parts are needed to make it work?
Thanks Joe
Thanks Joe
01-06-2010, 10:47 PM
#19
Here is something I found while researching this same question
The PCM uses the signal to adjust idle speed based on whether the car is in gear or in park/neutral.
As soon as the PCM "sees" the car go in gear it drops the idle speed by around 100 rpm to prevent jerking going into gear, and to prevent tugging at the torque converter.
It can be considered as optional on a swap. As long as the line is left open the PCM will always assume the car is in gear, and will drop to lower rpm when the engine is started. This also causes a much quicker rpm rampdown on a cold engine start.
Some aftermarket wiring harness companies that have no clue as to how the PCM works will wire this line to ground which makes the PCM think the car is always in park or neutral. On some applications this allows some diagnostic tests to be skipped (EGR, purge, etc.) so that these items can be left off without setting a code. The problem is that the idle is too fast then, and the car wantts to pull a little when sitting still, as well as other issues.
The PCM uses the signal to adjust idle speed based on whether the car is in gear or in park/neutral.
As soon as the PCM "sees" the car go in gear it drops the idle speed by around 100 rpm to prevent jerking going into gear, and to prevent tugging at the torque converter.
It can be considered as optional on a swap. As long as the line is left open the PCM will always assume the car is in gear, and will drop to lower rpm when the engine is started. This also causes a much quicker rpm rampdown on a cold engine start.
Some aftermarket wiring harness companies that have no clue as to how the PCM works will wire this line to ground which makes the PCM think the car is always in park or neutral. On some applications this allows some diagnostic tests to be skipped (EGR, purge, etc.) so that these items can be left off without setting a code. The problem is that the idle is too fast then, and the car wantts to pull a little when sitting still, as well as other issues.
Personal experience has shown that there is not much of an issue leaving out the PRNDL. I do notice a quicker ramp down on idle speed (especially on DBW engines) (I would assume high idle on cold startup is to help get the cats up to temp). I've never noticed an engagement problem at all.
I've not had issue on LT1, Vortec 5.3 at all (cable or DBW), unless they had aftermarket cams.
