robwormald

Hi all - I recently finished a rebuild of the motor of my 86 22RTE-C 4x4 pickup. At the same time I rehabbed the main engine wiring harness and fixed a bunch of corroded crimps and replaced all the connectors I could find.

This is an auto truck and thus did not come with a starter relay installed. Previous to the rebuild I'd been having intermittent starting issues and with the excellent threads from @RAD4Runner I spliced in a relay as a temporary fix, and while it improved things it didn't really solve the problem.

While I had the engine harness torn down I did a more proper job and cleanly wired in a waterproof relay in between the ECU and the starter solenoid and wrapped it up nicely so it looks factory. Once I put the motor in the truck it failed to start and after I'd stopped hyperventilating I narrowed things down to the neutral safety switch. As a test I disconnected the NSS connector and jumped it on the engine side of the connector, and the truck immediately fired up. This enabled me to get the truck started up and broken in.

One thing I noticed is that while the starter solenoid works with the key in the START position (as expected, because it's got a very direct, relay driven connection), the Circuit Opening Relay (and thus the fuel pump) do NOT trigger - the truck has to crank for 5+ seconds. I confirmed this by jumping the FP test connector (which causes the FP to come on with the ignition switch) and again the truck starts right up. It also appears the Cold Start Injector isn't firing, and I've confirmed that the CS injector-time-switch is working as expected - it would seem that the injector isn't getting the 12V signal from STA.

At this point I panicked a little (again) and wondered if I'd gotten something wrong when rewiring the harness, but after a lot of staring at circuit diagrams and reading a lot of posts I began to wonder if the NSS being out of the loop was causing these issues (in other words, did jumping the NSS also disconnect the COR / CSI from the STA circuit). This didn't really make sense as I only saw 3 pins on the NSS, but after pulling it out of the truck I was surprised to find it had *two* connectors coming from it: the usual 3-pin with in/out STA and reverse, and another 6-pin connector which I can find zero documentation about.

I've cleaned the NSS and got it back to working condition, and I can more or less work out the expected signals by "decoding" the pattern of the copper contacts, but at this point I'd like to understand what all these wires are doing.

If one or more of them ends up at the COR/CSI then this would seemingly solve my problems, but I'm learning to assume very little as I restore this truck! If not, I fear I've missed a splice in the harness, but I'm reasonably confident I haven't...

tldr: does anyone have a pinout / diagram that covers the 6 wires coming out of the NSS that aren't STA/reverse? My 88 FSM doesn't seem to cover it at all. This truck also has an ECT so it's likely some of them work with that, but I haven't been able to find a color coded diagram on that either.

robwormald

Note that in my circuit, I added the relay to the "end" of the battery -> starter solenoid circuit, so from

Battery => Ignition Switch => NSS => Starter Solenoid

became

Battery => Ignition Switch => NSS => Relay Positive Trigger
and
Relay Hot => Starter Solenoid

In other words, I'm not sending the 12v from the relay back through the STA circuit, it goes direct to the starter solenoid.

What I don't know is where in the circuit the "forks" to the CSI/Circuit Opening Relay are, and if maybe I should get the 12v coming out of the relay spliced into those forks instead, like I did for the starter.

Jimkola

I believe what you’re holding is the Transfer Position Switch. I’m guessing it performs the same function as a NSS, but connections are very different. I haven’t found that switch in the EWD book, yet.
The EWD will give pin locations.

robwormald

thanks, but it's definitely the neutral safety switch. It's on the passenger side of the transmission (the transfer position switch is on the transfer case on the driver's side)

Jimkola

I can not find those connectors for a NSS in my EWD. I must be missing something, just not sure what.

robwormald

hah, that's pretty much how I feel at this point.

fwiw I cleaned it up and reassembled / adjusted it, and it works as intended (at least for the neutral / park / reverse signal). still unsure on the second harness!