Reliable starter relay

[Black_Sheep]

So I bought a couple of AZ relays. I will replace one, keep one for a spare and pull apart the original one and see if I can clean it up. If it cleans up good then I'll re-install it.

There is literally not much to a starter relay. Inside is a pulling coil and a set of contact points. Mine failed a couple years ago so I sourced an NOS replacement. Once the car was up and running, I was curious and disassembled the original 55 year old relay. There was no rust or corrosion inside, except the contact points looked a little dirty. I dragged a flat file across the points a couple times to clean them up and tested it numerous times using a Milwaukee 12 V battery. It worked every time. The original relay got put back together and saved in my box of spare parts.

 

[JC Boatguy]

There is literally not much to a starter relay. Inside is a pulling coil and a set of contact points. Mine failed a couple years ago so I sourced an NOS replacement. Once the car was up and running, I was curious and disassembled the original 55 year old relay. There was no rust or corrosion inside, except the contact points looked a little dirty. I dragged a flat file across the points a couple times to clean them up and tested it numerous times using a Milwaukee 12 V battery. It worked every time. The original relay got put back together and saved in my box of spare parts.

Relays can malfunction for several reasons...weak signal from the key switch, weak coil inside to pull the contacts together, dirty or corroded contacts giving an intermittent signal to the starter. After seeing them fail in the marine world many times, I would open them up after acting up, every time the two copper contacts were "black". No continuity when the solenoid is energizied. No volts to the startrer. JMHO. John

 

[Jeff K]

This is my old starter relay, it's a 4 wire version. In my case the contacts failed in the closed position. Car would not stop cranking over unless I disco'd the battery cable. After taking it apart and cleaning, it works fine now. I saved it just for reference. It's been my experience that most of them fail open (no crank), rather than closed.

At any rate, you can see how it works. The coil gets energized and closes the breaker points. This connects the BAT wire to the SOL wire internally through the closed points.

 

[OneWheelPeel]

I agree, it claims "Made by an original Mopar / Chrysler supplier" so even if thats true doesn't mean its exactly the same as stock. I just impulse bought it so we will see how it goes.

Well the one thing I can say is original manufacturer or not the guy sucks at packing. It came in a small bag with bubble wrap and a terminal was bent in shipping.
For the money I would expect a little box or something to protect it better.