I've posted a picture of an aftermarket starter booster solenoid(relay) that I want to install on my 914.
-I don't have any wiring diagrams for this relay
- I understand the the 2 larger studs on each side will be for the large battery to starter cable.
- My question is on the 2 smaller studs on the front of this relay. Are these 2 for the yellow starter wire? At the base beneath these 2 small studs is the letter L and the letter R.
-Does any one have a wiring diagram or know which wire connects to these small L and R posts? I don't want to wire this thing up wrong. Thanx L.
Click to view attachment

http://www.914world.com/bbs2/index.php?showtopic=259055

Correct on the 2 larger studs. One smaller stud takes 12V from the ign switch and the other is probably a ground.
I expect the solenoid you show dies not connect the case to ground, so need the ground wire.
I guess the Ford solenoid frequently quoted does ground the case to ground as no wire shown
Should not matter which. Test it out with your jumper cables to confirm for that.

You have in essence:

- A heavy duty, high current capacity relay to energize the motor-mounted solenoid. However, the current needed to energize the solenoid is only < 5A. The Ford-type relay is fine but IMHO, total overkill - it's purpose was to carry full battery current to the Ford-type starter motor (no solenoid).

With an overrunning clutch-type starter (solenoid on starter), the main objective is to provide full battery voltage to energize the solenoid and reduce/eliminate any voltage drop due to the length of the control wire (yellow, from switch). A threshold voltage drop in the yellow wire circuit can prevent the starter solenoid from energizing resulting in a no-op starter motor.

- A Bosch-type relay is used to create a shorter current path from battery to solenoid. Using the existing battery cable connection at the solenoid is a shorter path than using the relatively thin, 16 ga. wire connection from ign. switch to solenoid (about 6+ feet).

- The schematic above illustrates moving the battery cable from starter solenoid to the Ford solenoid, then adding another short battery cable from the Ford solenoid to the starter solenoid. Additional connection points as well as longer battery cable contributes to more voltage drop.

- If an auxiliary add-on relay or Ford solenoid is under the chassis and not protected, that location invites more corrosion from road splash.

- An ordinary, $4 Bosch-type 25A relay should suffice to shorten the signal path to the existing solenoid.

Sherwood

Have you personally had a Ford solenoid fail due to corrosion? Really? In So.cal?

I've installed literally hundreds of Ford solenoids and have had only one failure due to water/corrosion.

That failure was on my own daily driver (8 winters), 1971 VW Super Beetle, that had been driven for at least 5 hard Canadian winters, of salted to shit roads before the solenoid failed. It failed due to being rusted so bad it fell apart.
Please note by this time I was also replacing one foot square sections of the inner fenders, because the wife was complaining of getting slush in the face while driving.

It's the only single failure I"ve ever had, but to be fair IIRC there was a member reported failure last year due to a cheap china made solenoid.
I have replaced a few bosch relays over the years and I agree I did suspect moisture in them, but those relays are meant to be kept high and dry.

The other excuses you have about the Ford solenoid , Meh... whatever floats your boat, do as you like, not worth arguing.

But on this newest excuse of yours about corrosion, I'm calling total

Cheers

I know this is way over board but when I built my LS1/G50/996 car I connected relays to everything. Head lights, brake lights, turn signals, starter, Just didn't want to depend on a old contact to carry a load bigger than a relay. I have had electrical problems in a car and it resulted in a fire.