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HELP Neutral Safety Switch

syndicate1

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Full Member
Joined
Feb 14, 2015
Messages
445
My '74 bronco is original with a 302 and c4 automatic. About 12-months ago, I replaced the original NSS because the reverse lights were not working. Since then, over the past 12-months, I've replaced the NSS switch 3x's. The third one stopped working this week and I'm onto the 4th NSS. Each time the replacement NSS's have failed, my truck won't start and there are NO signs fried wiring. So here I am scratching my head.

It's become a nuisance that has made me not want to drive my bronco for fear of being stranded on the side of the road, again.

I really need some technical advice about what to look for and insight about what could be causing multiple NSS switch's to go bad every 3-4 months.

Thanks!!
 
OP
OP
S

syndicate1

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Feb 14, 2015
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445
I think there's a run of bad NSS switches as I've had one fail quickly after installing as well. How close is your exhaust to the NSS?

Not close at all. I'm running a mostly stock exhaust, cast iron manifolds and 2 into 1 exhaust.
 

Rustytruck

Bronco Guru
Joined
Feb 24, 2002
Messages
10,875
People use to open up the stock Neutral safety switches and readjust the contacts as the non factory replacements had a bad reputation. Before swapping out the switches did you do a continuity check and prove them bad or unreliable? Did you try starting in neutral? Replacing 4 switches is more than bad luck. Is the failure to start on a hot restart? Or a cold start first thing in the morning. Also check your shifting collar in your steering column make sure it is shifting properly.

You can always make a jumper for the connector to bypass the neutral safety switch in an emergency but you have to be damn careful you don't start in gear.

If I was having these problems I would check the mag pickup in the duraspark if you run one. and or the wiring harness from the distributor/ coil to the fire wall. if those wires break down your shorting ignition to ground on the engine block.

I am assuming your getting a no crank situation so check to have a clean ground battery to body, battery to engine block and mounting starter solenoid to body. Got to have clean ground under the solenoid mount.
 

Skytrooper15

Full Member
Joined
Sep 13, 2018
Messages
216
Loc.
Tuscaloosa,Al
Neutral safety switch

I go along with Slowleak about opening one up and see what it looks like inside.But if you have a DC current ampmeter block the wheels good and for safety's sake get a helper to put on the parking brakes and also hold his foot on the main brake pedal and put the gearshift in reverse with the ignition on and see how many amps is the switch drawing.It shouldn't be enough to barely make a reading on the meter but if it's more than an amp or two you have a wire grounded going to the backup lights or the neutral switch.Be very careful while under the Bronco.
 

75MIKE

Sr. Member
Joined
Aug 22, 2001
Messages
955
Loc.
NE Washington
I'm sure you have tried turning the key to start position and running the shift lever slowly through the whole range to see if something has come out of alignment.

Just a thought.
 

Hotrodjohn

Full Member
Joined
Feb 12, 2016
Messages
264
I bought an aftermarket one because my original Ford one worked only the start but not the back up lights. So the aftermarket one lasted a few months and failed. I took it off and if you shake it it sounds like a rattle can. I put the 43 year old Ford one back on and it starts, but no back up lights...... lol... Ive seen some OEM Ford ones on ebay for around 100.
 

Hotrodjohn

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Feb 12, 2016
Messages
264
I found a Motorcraft on ebay and bought it. It feels twice as heavy as the aftermarket one that lasted a few months.
 
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syndicate1

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Is 4th time the magic number? Thanks to WH for customer service exchanging the 3rd faulty NSS. Installed a 4th NSS this weekend. Clearly there is a bad batch out there. Fingers crossed. In the mean time, I found two NOS Motorcraft NSS switches on the interweb and bought both of them.

Agree with @Hotrodjohn the Motorcraft NSS feels twice as heavy compared to the on WH sells.

After searching online about NSS switches.

1. TBP sells NSS's for $44.95. Mfg. unknown. The image on Tom's website is unbranded and looks like the same NSS that WH sent to me.

2. NAPA sells Echlin NSS's for $102.99. Echlin is owned by Standard Motors

3. O'reilly's sells Borg Warner NSS's for $91.99

4. Rock Auto sells Standard Motors NSS's for $68.99

5. Rock Auto also sells WVE/AIRTEX/WELLS NSS's for $151.79. Based on the images on Rock Auto the housing of this NSS appears more robust. They even go on to write, "While two switches from two different manufacturers might appear to be identical, there are several key quality characteristics you can’t see. Each Airtex/Wells switch is manufactured from the OEM-preferred blend of nylon and glass-filled plastic for exceptional strength and includes premium copper/nickel/silver-plated electrical terminals to ensure robust electrical connectivity."

6. WH sells NSS's for $54.99. MFG unknown. The WH image shows "Ford" stamped on the NSS. The NSS sold to me does not have "ford" stamped on it. The actual WH NSS looks like the image shown at TBP, NAPA, O'reilly's, and Rock Auto which could mean it's made by Echlin or Standard Motors.

I learned the following and found myself asking.....

1. Pricing at national auto parts stores is relatively the same, 40% - 50% more than national auto parts stores.

2. Pricing at WH and TBP is relatively the same, 40% - 50% less than national auto parts stores. How is this possible? This deep discount surely can't based on sales volume. Based on Rock Auto's pricing for the Standard Motors NSS, is it safe to presume the NSS sold by WH and TBP are mfg by Standard Motors?

3. Does anyone know the mfg of WH's NSS's?

4. Does anyone know the mfg of TBP's NSS's?

5. Does anyone have experience with expensive the WVE/AIRTEX/WELLS NSS's? Yes they are twice as much. If the quality control of this NSS is truly better, I would gladly have paid twice as much for one NSS compared to the inconvenience and time spent removing and replacing four NSS's.
 

DirtDonk

Contributor
Bronco Guru
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Nov 3, 2003
Messages
47,345
Well, I can't say I heard that we switched brands, but I thought we were selling Scott Drake brand and selling them in their packaging instead of generic packaging.
Perhaps the SD parts were the ones that were failing so regularly? And SD also has a habit of putting Ford part numbers on their products, which seems consistent with the picture on our site.

I have one here (in SD packaging) that I could weigh if we needed to compare.

Paul
 

tirewater

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Jan 28, 2011
Messages
1,040
Loc.
San Francisco Bay Area
My bad switch was a Standard Motor Products version, which sold for ~$75. The replacement is the Scott Drake (from Tom's Bronco), sold for ~44.

The two switches look nearly identical, although there was slight color variation of the red plastic section.

The SMP version didn't strand me, but the reverse lights quit working. When I removed the switch it had started to split along the seam of the case.

Given the tight fit of the switch on the transmission shift shaft, there is a possibility of the switch binding upon install if the case is canted or the action of the switch is not true/normal to the shifter shaft.

Is 4th time the magic number? Thanks to WH for customer service exchanging the 3rd faulty NSS. Installed a 4th NSS this weekend. Clearly there is a bad batch out there. Fingers crossed. In the mean time, I found two NOS Motorcraft NSS switches on the interweb and bought both of them.
 

Hotrodjohn

Full Member
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Feb 12, 2016
Messages
264
imo: find a NOS Motorcraft and be done with it... the extra cost just hurts for awhile.
 

Lawndart

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Nov 23, 2014
Messages
836
Loc.
66030
I'm tagging onto this thread as I just had an issue with mine. Mine is original and has not been replaced in the past.

Out camping with a friend. Go to start after fishing, turn the key - nothing. Fiddle with the position lever (quite a bit) and it starts. Next morning getting ready to leave to fish - nothing. Fiddle - nothing. Remembering the day before, I suspect the NSS. I impress my friend using a screwdriver to activate the solenoid. We go, we fish. I start it again with the screwdriver after fishing to get back to camp. At camp, I pull out the schematic that I keep in the glove box - - - - - there is nothing in the schematic about the NSS. I pull out my multimeter and after a few minutes and some help from my friend turning the key, I figure out the terminals to jump to bypass the NSS.

Crap like this bugs me and to be honest, the lack of documentation on the schematic bothers me the most. I knew I had an original Ford copy of schematic at home as well as original manuals. I looked last night - - - there is nothing in any schematic about the NSS, ugh. I think - check out seabiscuit68 on a '74+ instead of a '73 - - still nothing on the NSS.

I attempt an adjustment using a drill bit to confirm neutral - no change.

I take it off. It did not feel right when I actuated it by hand. I bench tested it - failed continuity.

Decided to take it apart. It is not easy. There are several pot metal tabs to bend and two rivets to drill out. I took my time and got it apart. One of the sprung contact barrels was out of position and loose in the body (how, I do not know). The body was also full of greasy gunk. I completely drilled the rivets out and made through holes and cleaned thoroughly. The gasket was still there, but I added a little of silicone during reassembly. It is quite fiddly to position the two sprung contact barrels and reassemble. A couple of zip-ties and some patience and I was able to do it. Tapped the metal tabs in place and installed pop-rivets to replace the original body rivets. It felt much better when actuated and when bench tested, it worked fine. I used a syringe and put some contact grease inside via the neutral finding hole.

Installed - starting and backup lights are working properly again.

Lessons learned -
- unplug the NSS and jump the two red'ish colored wires (when looking at the NSS harness) to bypass (one above the other, one male and one female).
- even factory schematics are not complete - there is nothing showing an interrupt between the ignition switch and the starter relay.
 

Slowleak

Bronco Guru
Joined
Sep 12, 2013
Messages
3,732
Loc.
Georgia
The 75-77 schematic has the NSS. It’s in the lower left (G4) above the starter motor......

eb1dae7c8390a8ab9afe530646b5636b.jpg
 
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