Swapping pedals wiring question

[NJ C10 Guy]

I am swapping out my manual brake, hydraulic clutch pedal assembly for an automatic brake assembly with vacuum assisted brakes. I can see between the two assemblies there are differences in the wiring connections. For instance, the brake switch on the manual has 2 prongs, the brake switch on the automatic has (2) sets of 2-prong switches. I think one of those is brake the other is cruise control? The other connections that bolt up next to the brake pedal are different as well. The manual one has (3) separate connections, the automatic has a black plastic box and beneath it there is a 2-prong and a 3-prong connection, but it looks like the wiring harness in my truck doesn't have anything that will connect to these.

I can snap some side-by-sides later and post them unless someone knows what I'm talking about beforehand and can help me out before I bolt everything up. Thanks in advance.

Side note: My reverse lights are on a toggle switch in my ashtray if one of those would be for the reverse lights for some reason.

[hatzie]

Originally Posted by NJ C10 Guy

I am swapping out my manual brake, hydraulic clutch pedal assembly for an automatic brake assembly with vacuum assisted brakes. I can see between the two assemblies there are differences in the wiring connections. For instance, the brake switch on the manual has 2 prongs, the brake switch on the automatic has (2) sets of 2-prong switches. I think one of those is brake the other is cruise control?

Correct 1 pair for Brake Lights 1 pair for Cruise control.

Originally Posted by NJ C10 Guy

The other connections that bolt up next to the brake pedal are different as well. The manual one has (3) separate connections, the automatic has a black plastic box and beneath it there is a 2-prong and a 3-prong connection, but it looks like the wiring harness in my truck doesn't have anything that will connect to these.

I can snap some side-by-sides later and post them unless someone knows what I'm talking about beforehand and can help me out before I bolt everything up. Thanks in advance

Please do...

Originally Posted by NJ C10 Guy

Side note: My reverse lights are on a toggle switch in my ashtray if one of those would be for the reverse lights for some reason.

The Neutral Safety/backup light switch that can be found on the base of the automatic steering column...

You'll need the "Neutral Safety" starter interlock on the Automatic column wired such that it interrupts the "Start" wire when the truck is not in Park or Neutral. If the clutch pedal has a starter interlock safety switch that cuts starter power when the pedal isn't pressed to the floor move the wires to the neutral safety switch on the column. It's not as optional as the clutch interlock.

The backup lights on an automatic tranny truck are wired to the backup light terminals of the Neutral Safety switch on the bottom of the steering column.

[NJ C10 Guy]

I have an automatic column, but there is definitely no neutral safety switch on it. I just looked (it's out of the truck and in my garage). Can I just buy one and stick it in there?

Edit: When I bought the truck it had the original 3-speed manual column, but the truck was a 4-speed on the floor. I picked up the auto tilt column after I bought the truck, not knowing about the NSS. Just by the way things are looking, I'll have a really fun learning experience with wiring this bad boy...

[hatzie]

If it's a column with the mechanical starter lockout it may only have a backup lamp switch. You should be able to buy the right year part and fit it back on the column.

[NJ C10 Guy]

Originally Posted by hatzie

If it's a column with the mechanical starter lockout it may only have a backup lamp switch. You should be able to buy the right year part and fit it back on the column.

Guess I'll be picking this up tomorrow. I'll post the pics of the 2 different columns as soon as I can.

http://www.pepboys.com/product/details/8482983/00050

[jetmech85]

It depends on the year of your automatic column. I haven't been able to determine exactly what year that the neutral safety switch was deleted. My computer monitor is so lousey it blurs out the wiring diagrams when I make them large enough to read so I just have to look at the parts trucks I have. I have an '85 without it. The key won't turn to the start position unless it is in park or neutral. It has a reverse light switch that looks like a neutral safety switch but no contacts moulded into it. New replacement switches have the contacts because they fit mutiple years. Since you removed a hydraulic clutch pedal assembly I assume you are working on at least an '85.

[NJ C10 Guy]

My truck is an '86. The column I got is allegedly out of an '87, so that would make sense that the NSS isn't there by what you said. In that case, do I need the part I linked above? Should there at least be something in the place where the NSS is typically located?

[NJ C10 Guy]

Ok, here is what is currently in the truck, from the manual assembly. I removed this from the side of the brake pedal assembly to help me remove it easier:



Back view of current setup:



Auto pedal assembly:

[jetmech85]

The only purpose the switch serves is back up lights unless you have a throttle body. If you do then it comunicates with the computer. The replacement switches will have all the functions but not needed in your case. You will have to make a jumper wire for your existing clutch pedal lock out. (purple and yellow wires) I have seen the devices you are showing but I don't know their function. I'll bet hatzie will be able to guide you on what you have and what you need.

[hatzie]

Since it was originally three on the tree the backup lamp switch was on the base of the column just like the dual function neutral safety/backup switch... If the original Packard 56 backup lamp plug wasn't cut off it may just plug in.

The neutral safety switch should interrupt the Purple (usually) start wire from the ignition switch. Many (but not all) of the manual shift trucks had a clutch safety switch that interrupted the same wire. You couldn't run the starter till the clutch pedal was pushed down. If yours has one of those you can just move the wires to the neutral safety switch.
Otherwise you'll have to interrupt the start wire between the ignition and the big square firewall plug or live with the fact that you can engage the starter with the shifter in Drive, Low, or Reverse. If your wiring skills are not that good I would consider acquiring this wire, with the safety switch plug in the middle, from an Auto Trans donor chassis. You can release the terminals at the bulkhead and the ignition switch plugs fairly easily and then remove the wire from the harness without damaging anything else.

[hatzie]

The year would be darn handy...
Looks like it's from the 80's

Originally Posted by NJ C10 Guy

Ok, here is what is currently in the truck, from the manual assembly. I removed this from the side of the brake pedal assembly to help me remove it easier:

The round can is probably the hazard flasher... Definitely one of the flasher relays. The black rectangular unit on the right is likely the seatbelt buzzer. GM Part # 344813 is a horn relay.
You need these...

Originally Posted by NJ C10 Guy

Auto pedal assembly:

Large box with the card edge connector is likely Cruise control. Not sure what the relay is. Is there a part # on either piece?

[NJ C10 Guy]

Originally Posted by hatzie

The year would be darn handy...
Looks like it's from the 80's


The round can is probably the hazard flasher... Definitely one of the flasher relays. The black rectangular unit on the right is likely the seatbelt buzzer. GM Part # 344813 is a horn relay.
You need these...




Large box with the card edge connector is likely Cruise control. Not sure what the relay is. Is there a part # on either piece?

I put it in another post not my original, but my truck is an 86 and the auto column I bought is allegedly from an 87. The can says hazard next to it, and the rectangular unit says buzzer, so you're on the money there. I'll check the relay for a part number and let you know.

While digging around, I also found a thicker gauge yellow wire and purple wire that were wired together at the relay and taped up. Is this the starter and clutch safety switch you were talking about?

Looks like I'll have to take some more pics and get some more info for you. Thank you very much for the help thus far.

[jetmech85]

Yes the thick yellow and purple wires went to the clutch safety switch, I have seen these wired together probably due to the fact that the switch went bad and was a quick fix to get the truck to start. Mine was wired together with a red wire nut. My thoughts are you don't need a neutral safety switch due to the fact the '87 column won't let you turn the key to the start position while in gear but I could be missing something.

[Chevy3+3]

Originally Posted by jetmech85

The only purpose the switch serves is back up lights unless you have a throttle body. If you do then it comunicates with the computer. The replacement switches will have all the functions but not needed in your case. You will have to make a jumper wire for your existing clutch pedal lock out. (purple and yellow wires) I have seen the devices you are showing but I don't know their function. I'll bet hatzie will be able to guide you on what you have and what you need.

Not trying to hijack the thread but had a question

I haven't started my manual tranny swap yet but I do have a TBI truck. So are you saying the neutral safety switch communicates with the computer? So if I remove a set of Auto pedals and install a manual pedal assembly will my computer not allow the truck to start? I am told my trucks harness should be prewired for a clutch safety switch. If I connect it to my manual pedals everything should work correct?

[hatzie]

Yup... The column and cab years are very important info.
The 87 AT column should have a mechanical interlock to prevent the ignition tumbler from turning to the start position when she's in gear. This makes the neutral safety unneeded. You still need it to get backup lamps and it's the same part.
Just make sure the clutch safety switch wires are firmly attached together. I've usually just removed the clutch switch from the pedal brackets and tied it to the harness with a chunk of tube taped over the threads to keep the plunger from being pushed in.

You can read the 86 MT pedal bracket horn relay part #...
The steel can on the AT pedals is an odd critter. It may just be an 87 horn relay... I'm just curious.

[Chevy3+3]

Originally Posted by hatzie

Yup... The column and cab years are very important info.
The 87 AT column should have a mechanical interlock to prevent the ignition tumbler from turning to the start position when she's in gear. This makes the neutral safety unneeded. You still need it to get backup lamps and it's the same part.
Just make sure the clutch safety switch wires are firmly attached together. I've usually just removed the clutch switch from the pedal brackets and tied it to the harness with a chunk of tube taped over the threads to keep the plunger from being pushed in.

So if your doing that with the clutch safety switch then the truck could be started in gear correct?

[hatzie]

Originally Posted by Chevy3+3

So if your doing that with the clutch safety switch then the truck could be started in gear correct?

Yup. It's allowed me to creep the trucks forward a few inches using the starter with the pump cutoff or HEI coil power wire removed. No different than older trucks without the anti lawsuit switches.

[Chevy3+3]

Originally Posted by hatzie

Yup. It's allowed me to creep the trucks forward a few inches using the starter with the pump cutoff or HEI coil power wire removed. No different than older trucks without the anti lawsuit switches.

As long as I am the only one driving it I would be fine doing that but if my daughter turn the key while in gear with a TBI truck theres a good chance it may start and take off, lol

So my truck is a 88' v30 factory auto......the replacement manual tilt column I am swapping in is from an 84'. Anything special I need to do for that column to work?

[jetmech85]

I havent seen an automatic wiring harness that was prewired for a clutch pedal lockout switch but not saying it doesn't exist. As far as the neutral safety switch and throttle body, the computer will adjust idle speed if it is in park or neutral or in gear. Years ago my wife jumped in my manual truck to move it, hit the key without pressing the clutch pedal. It started in gear and she hit the back of her car. That was interesting to try explaining that one to State Farm.

[Chevy3+3]

Originally Posted by jetmech85

I havent seen an automatic wiring harness that was prewired for a clutch pedal lockout switch but not saying it doesn't exist. As far as the neutral safety switch and throttle body, the computer will adjust idle speed if it is in park or neutral or in gear. Years ago my wife jumped in my manual truck to move it, hit the key without pressing the clutch pedal. It started in gear and she hit the back of her car. That was interesting to try explaining that one to State Farm.

I was my understanding that an automatic harness has a prewired 2 prong plug that is around the ash tray location under the dash for the clutch safety switch.

[jetmech85]

I have an '81 and an '85 manual shift trucks. Both have a yellow wire and a purple wire going to the clutch switch. They are heavy gauge wires. 8 or 10 ga. I have never seen that in an auto harness. Again, the disclaimer, that has just been my experience. If it were my truck I wouldn't bother wiring a clutch switch but I like the old school way. Not sure when the squares began using it.

[hatzie]

The AT neutral safety is taken care of by the mechanical lockout on the 87 column.

The clutch safety switch is just like many other features mandated by the decline in common sense... Like my lawn mower that requires two people to start... I've gone back to using a line trimmer to mow the section that required that mower.

My 76, 78, 79, 80, 81, & 84 VW Rabbits didn't have a clutch safety switch. I'd have to check the 05 Jetta but it probably does. My 61 & 64 Dodge, 68 & 73 Ford, and my 73 & 75 GMC trucks didn't have them. All of the "Big three" probably added them in the '80s in response to their legal departments or mandates from our nanny government like the seatbelt reminders and seatbelt starter lockouts starting in the '70s or tire pressure monitors in the last decade.

Lawyers getting into the design process to prevent accidents from folks that don't use common sense...
If you're not leaving it in gear rather than using the E-brake then it's not an issue. My 76 Rabbit broke me of that habit early on. The windshield leaked into the fuse panel and engaged the starter with obviously bad results. I've never left a car in gear again.

[NJ C10 Guy]

Originally Posted by hatzie

Yup... The column and cab years are very important info.
The 87 AT column should have a mechanical interlock to prevent the ignition tumbler from turning to the start position when she's in gear. This makes the neutral safety unneeded. You still need it to get backup lamps and it's the same part.
Just make sure the clutch safety switch wires are firmly attached together. I've usually just removed the clutch switch from the pedal brackets and tied it to the harness with a chunk of tube taped over the threads to keep the plunger from being pushed in.

You can read the 86 MT pedal bracket horn relay part #...
The steel can on the AT pedals is an odd critter. It may just be an 87 horn relay... I'm just curious.

Ok, so it sounds like I don't need the NSS since the column stops the truck from starting in gear. For the backup lamps, since they are already on a toggle, can I just leave it alone or do I need to connect it to something?

Unfortunately I installed the brake pedal and vacuum/MC yesterday and I can not get a good picture or check for a part number. What I plan on doing is removing the cruise control module and putting the hazard/buzzer/horn relay from the manual assembly in its place. When i do that and crawl under there I will do my best to grab a part number. Hopefully, those relays on the auto assembly are not needed, or maybe I could hook up the clutch/starter wire to the 2-prong one? If there's anyone who has an automatic that can look at their assembly and let us know what's connected that would be pretty awesome.

[hatzie]

Put the NSS in and plug in the backup lamps. I'll be surprised if it passes NJ safety inspection with them on a toggle switch.

The steel canister relay that came with the AT pedals is unlikely anything you need.

[NJ C10 Guy]

Ok. Here is how the back up lights are wired to the switch now:



The black wire I traced and it's a ground. The yellow wire I believe runs back through the firewall (have to double check on that) and the white wire connects after a short time to a pink wire. The purple wire you see coming off in the picture below goes to the connection for my stereo:



I will pick up a NSS, solder and extend the wires so they hook up, if it will eliminate the need for me to hit a toggle switch when I put it in reverse. Mostly because it's easier to forget to turn it off after I'm done backing up lol.

BTW, New Jersey has eased up dramatically on their inspection guidelines. Now they just check emissions, which I would most likely fail. If I register it as historic, which I can and soon will because it's older than 25 years, it's exempt from inspection.