At 4:30 this afternoon, I received a phone call from the mechanic who has had my Dart for the past two weeks. Many of you who have followed my posts at this SS topic know the headache and time I put into getting the car to run. Unfortunately I could not get to the shop before 5:00 close, so it will be Monday before I retrieve the car.

The mechanic is Eric. He is in his early fifties and claims he is familiar with the 74 cars. The first thing he told me was the car would not crank because the ECU was dead. He had to replace it. Very odd. Two days before I took the car to him I put a brand new Standard Bluestreak 5 pin ECU on the car. This was the third ECU I tried in many months of attempting to get the car to run. He put in the fourth ECU and disconnected the wiring connector that plugs into the seatbelt interlock unit on the driver side fender between the ballast resistor and the wiper fluid bottle and the engine fired and ran. He told me he reinstalled my Bluestreak ECU and it would not fire. He seems to think the Bluestreak went bad because he thinks there is a short in the seatbelt interlock unit and I probably ruined the Bluestreak by many attempted cranks prior to taking the car to him. He advised me not to re-plug the interlock unit for fear it may short the fourth (good) ECU.

Does this sound correct? Could that damn interlock short out three previous ECUs?

He also changed the neutral safety switch. I'm not sure if it was the switch or the plug. I'll find out Monday.

hallelujah !

That is great news. Keep us posted on the finer points of the "fix".
I bet you are over the moon with the news?

regards,Rod

I was curious to know the source of your problem and thought a wiring diagram would help. I looked over '73, '74 and '75 Dart diagrams and none showed the seat belt interlock system. I thought the interlock system simply prevented cranking by keeping power from reaching the starter relay and was trying to verify this.

_________________
Joshua

Yay! Glad to hear it.

Joshie, when Eric explained to me that he finally determined the interlock system was the culprit, I was not convinced. When I took him my car two weeks ago, I also brought him my 73 FSM (my car is a 74) and several SS wiring and Mopar wiring diagrams that I have used and traced with my handwritten notes and findings on my car. I told him I didn't have the 74 FSM and he actually pulled up several diagrams and charts on his computer while I was there assuring me he had the necessary charts. One thing he mentioned to me yesterday was he could not find anything in his reference materials about the interlock system. He did not even know that in order to start the car, you had to unbuckle and rebuckle the seatbelt each time the ignition was turned OFF. (When the car was delivered to him, the middle passenger belt was plugged into the driver buckle.)

In years past, when my car was working properly, if you tried to crank the car with the seatbelt not buckled, nothing happened when you turned the key. Plug in the seatbelt and then the starter would turn. Seatbelt not plugged in, turn the ignition to START, no click, nothing. Obviously that was the way it was designed to operate. A couple of years ago SS Dan referred someone here to a technical bulletin (I think) about the seatbelt interlock. Using the SEARCH function, I have tried to access that link, but it is no longer a valid link. Maybe Dan could help us find that link again.

Dan? This is the old post site that no longer works here.

Slant Six Dan. Do you have your ears on? Is the information on seatbelts in one of your previous posts available elsewhere?