Puzzle, Mystery relay, not on my wiring schematic.

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garyfish340

garyfish340

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There's a relay attached to my relay. All I can tell you is, on the Red plug there is a yellow wire going to the middle bulkhead connector 2nd wire down on the right, it also jumps from the red plug on the mystery relay to the starter relay. Than there is also a yellow/black wire it goes to the passenger side bulkhead connector, top left wire, than there is a little brown wire that I swear I didn't cut, it must have been gremlins.Those are all on the red 3 prong connector. Than there is a brown single prong connector with a bigger brown wire, and it goes to the drivers side bulkhead, first wire to the right. Could this be for the window wash fluid motor, a pace setter, a city horn, or air conditioning. This car is originally a 1975 Plymouth Duster, slant 6. w/ air conditioning. Automatic trans.
 

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Yes that is the seatbelt interlock which likely has been disconnected under the seat. It's intention was to prevent the starter from operating until the belts were fastened.

Unfortunately it also occasionally prevented the starter from operating WITH the seatbelts fastened, so when that happened you popped the hood and pressed the red button you see sticking out of the relay box. That gave you one "free" start.
 
TylerW said:
Yes that is the seatbelt interlock which likely has been disconnected under the seat. It's intention was to prevent the starter from operating until the belts were fastened. Unfortunately it also occasionally prevented the starter from operating WITH the seatbelts fastened, so when that happened you popped the hood and pressed the red button you see sticking out of the relay box. That gave you one "free" start.
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I'm not laughing at you, I'm laughing at the definition you gave me. If you don't use the seatbelts, the car won't work. We used to call these 75 duster seatbelts suicide belts. The retractor will not retract no matter how hard you yank em, so you just have to trust that if you get in a accident they will work, and where the shoulder belt goes over the top of you shoulder, and back down to the floor, the only thing that holds those two belt together for adjustment is a plastic clip, which always broke when you tried to adjust the belt. ( one of mine is missing. ) SO IF THE CAR WON'T WORK WITHOUT THE SEAT BELTS, WHAT MAKES THE SEAT BELTS WORK ? Thank you so much for the answer, everybody. This relieves a ton of stress off me. I guess it's not in the schematic out of sheer embarrassment by the engineers.
 
I actually had the opportunity to speak to someone who worked on these cars at a dealer way back when. He didn't say that the interlock was recalled, but he did say that the engineers came up with a fix for the dealers, because the customers hated this thing. apparently the way he said it was supposed to work was - If the seat belt wasn't on, and the car started, within 30 seconds, you would have to get out, and reset the interlock with the red button. He also thought that he recalled a plug that plugged into the interlock, and than the regular plugs would plug into that, and the idea was to jump the yellow and the brown wires together.
Mind you this is after I looked at the schematic I had for 1975 Dodge, and noticed that it just had the yellow wire running to the relay, and no interlocking system mentioned. So I cut the yellow black trace, and the browns, and just sent the yellow from the bulkhead directly to the starter relay. I'm fairly certain the system was disabled years ago, but I may have screwed things up. I may soon be in there with a probe searching for live wires, when the engine doesn't start. Ouch !
 
CudaDust said:
Man that stinks! Hope all is well and nothing is messed up.
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Everything is a learning curve right ? I spent years, and years ripping apart, and building E body cars. Granted, 20 years ago there was a lot less technical modifications that were available to mess with. This whole project has been a matter of doing everything twice. There's an awful lot of retro fitting, and than there's a bunch of historic information fading into the sunset as time marches forward. Hopefully by the time everything is finished, they don't throw a whole new evolution level of hot rodding on top of what's currently going on.
 
Looks like you did the right thing per the schematic by sending the yellow wire for the L connection on the bulkhead to the L terminal on the start relay.

And, for grins, you might look under the seats and see if their is a switch under the seat on both front seats. These were weight-on-seat switchs; they bypassed the start-killing feature on that side if no one was in a seat.

This was all there to prevent starting without the seat belt fastened for any front seat passenger. It didn't kill the car after starting. I can remeber this being a big deal to disconnect and disable!
 
nm9stheham said:
Looks like you did the right thing per the schematic by sending the yellow wire for the L connection on the bulkhead to the L terminal on the start relay.

And, for grins, you might look under the seats and see if their is a switch under the seat on both front seats. These were weight-on-seat switchs; they bypassed the start-killing feature on that side if no one was in a seat.

This was all there to prevent starting without the seat belt fastened for any front seat passenger. It didn't kill the car after starting. I can remeber this being a big deal to disconnect and disable!
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The switches are still under the seat, but I don't believe they functioned. I drove the car with the slant 6 a little, and when I got the car, I think the seat belts were in a box of junk. So I drove home without them.
I guess why I brought this up to begin with, is because I've created a new wiring harness for the hemi, and there are a few extra wires, and plugs that I can't I.D., or that that I have, and want to remove cleanly, and hopefully have no SNAFU's on test day. I love the fact that when this motor was in my 69 there weren't a lot of wires under the hood. ( I had some clutter from a few aftermarket things. ) The fire wall had a tiny taped up harness. Thank you for posting ideas, and answers.
 
If anybody reads this further. There's more to it than just sending the plain yellow wire to the starter relay. A week later I tried to start the car, and nothing happened. After looking at the photo, it looks like the yellow, goes to the red plug, and the yellow/black goes to the red plug, since it's a 3 pin plug, the 3rd pin is a jump between the yellow, and yellow/black, and than the brown wire, brown plug goes into that taped up wiring, and up to the center connection on the starter relay. So I'm thinking that the yellow wire, and yellow/black need to be jumped. and if the brown ever did go to the bulkhead connector, I still may need that wire too. So I need to find taht too, if it exists.
I am so lost when it comes to wiring, and the thought that I may have clipped a wire, that I have no idea what it is, makes me sick.
 

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Look at your starter relay and check for the following connections:
1. Mid sized battery cable the biggest lug (with the bolt)
2. Mid sized wire from the medium sized screw lug to the starter's smaller lug
3. Yellow wire to the connection on the relay that sets at a 45 degree angle to the body. The way you describe the yellow wire as going to the " middle bulkhead connector 2nd wire down on the right" sounds right. The mymopar diagrem shows just one yellow wire from that middle connector. Trace that yellow wire on the other side and make sure it comes direct from the ignition key switch.
4. The last lug connects down to the Neutral start switch on the auto trans, or back through the firewall to the clutch switch for a manul trans that is activated by the clutch pedal lever.

No other connections are needed.

Your situation is simple to troubleshoot; you really need to do this to make progress so we know what is happening where:
--- Use a test light or voltmeter to verify you have power to the #2 lug above on the starter relay when you turn the key to START. If power shows up on #2 with the key in START but no start occurs, then the starter is bad or not connected.
--- If power does not show up at #2 then see if it shows up at #3 with the key in start
--- If it shows up at #3 and still does not start, then temporarily jumper the last terminal (#4 in the list above) to engine ground or chassis or battery - and try again.
--- If you have power at #3 and with the #4 terminal grounded, but no start, then the relay is bad.
--- If you have power at #3 and with the #4 terminal grounded, and is DOES start, then the NSS is bad or linkage misadjusted.
---If you don't get power at #3 at all, then the key switch or wiring from the key switch to #3 is bad.
 
nm9stheham said:
Look at your starter relay and check for the following connections:
1. Mid sized battery cable the biggest lug (with the bolt)
2. Mid sized wire from the medium sized screw lug to the starter's smaller lug
3. Yellow wire to the connection on the relay that sets at a 45 degree angle to the body. The way you describe the yellow wire as going to the " middle bulkhead connector 2nd wire down on the right" sounds right. The mymopar diagrem shows just one yellow wire from that middle connector. Trace that yellow wire on the other side and make sure it comes direct from the ignition key switch.
4. The last lug connects down to the Neutral start switch on the auto trans, or back through the firewall to the clutch switch for a manul trans that is activated by the clutch pedal lever.

No other connections are needed.

Your situation is simple to troubleshoot; you really need to do this to make progress so we know what is happening where:
--- Use a test light or voltmeter to verify you have power to the #2 lug above on the starter relay when you turn the key to START. If power shows up on #2 with the key in START but no start occurs, then the starter is bad or not connected.
--- If power does not show up at #2 then see if it shows up at #3 with the key in start
--- If it shows up at #3 and still does not start, then temporarily jumper the last terminal (#4 in the list above) to engine ground or chassis or battery - and try again.
--- If you have power at #3 and with the #4 terminal grounded, but no start, then the relay is bad.
--- If you have power at #3 and with the #4 terminal grounded, and is DOES start, then the NSS is bad or linkage misadjusted.
---If you don't get power at #3 at all, then the key switch or wiring from the key switch to #3 is bad.
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Trust me i'm not arguing any point here, and I don't pretend to understand electricity, but even I understand what you wrote there, it all makes sense, until it don't...
This is yesterday's excerpt from my build ( I use the world loosely ) Thread.------->>>>

10/14/2014 - So a starter relay is just an antiquated version of the good ole Bosche type relay, that I learned so much about from Jay. And theoretically, if you jump the start, and run with a screw driver, it should trigger. So I decided to test my theory by doing so. I got a screw driver in one hand, and a cup of coffee in the other, and so I jump the relay, and nothing happened. ( which made my heart sink ) But I guess I didn't do such a good job, and I didn't really make a connection. Cause as soon as I moved the screw driver, it triggered, I jumped, and coffee flew. So it works, and I'm covered in coffee, and if I had 10 more minutes of good light I'd fix this. Wooooo Hoooo !!! And tomorrow, massive rain.
 
For later reference, because somebody is going to read this. What I think is this little box separates the yellow from the yellow/black, and the brown plug excites them, allowing them to connect. ( don't take my technical verbiage seriously ) I'm guessing that's what the gremlins in this little box do. On the inside of the car, whatever is happening under my *** in the seat, should be nothing ( I hope ) it's unplugged. ( and it still sucks, just like when that band Green Day was unplugged.)
 

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All I know is even back 39 years ago, our stupid government was trying to reach up everybody's ***.
 
garyfish340 said:
10/14/2014 - So a starter relay is just an antiquated version of the good ole Bosche type relay, that I learned so much about from Jay. And theoretically, if you jump the start, and run with a screw driver, it should trigger. So I decided to test my theory by doing so. I got a screw driver in one hand, and a cup of coffee in the other, and so I jump the relay, and nothing happened. ( which made my heart sink ) But I guess I didn't do such a good job, and I didn't really make a connection. Cause as soon as I moved the screw driver, it triggered, I jumped, and coffee flew. So it works, and I'm covered in coffee, and if I had 10 more minutes of good light I'd fix this. Wooooo Hoooo !!! And tomorrow, massive rain.
Click to expand...

Yes it is a just a relay like the Bosch. (Bosche is a nick name for the Jerries...lol) SOunds like you need to drink the coffee BEFORE any auto work!

When you jumped the relay, did you put the screwdriver between the large stud and the next largest stud? (If so, you proved the starter is good.) But if you jumped elsewhere,, you may have proved more was good. Let us know.
 
nm9stheham said:
Yes it is a just a relay like the Bosch. (Bosche is a nick name for the Jerries...lol) SOunds like you need to drink the coffee BEFORE any auto work!

When you jumped the relay, did you put the screwdriver between the large stud and the next largest stud? (If so, you proved the starter is good.) But if you jumped elsewhere,, you may have proved more was good. Let us know.
Click to expand...
What you need to do is connect the yellow, and black, and the yellow - tied together, and plugged into the starter relay, the angeled male spade. In my case I just grounded the relay on the other spade----> Which is the spade for the neutral safety switch>>> Which grounds, and ungrounds the relay to make it a circuit.
So the brown wire on the interlock must come, or go to the neutral safty switch, and than the relay. I just need to unwrap that small circuit, find the brown, and connect it to the relay, and it'll work.
By grounding the relay the car is now running for diagnostic purposes.
 
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