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Discussion Starter #1
I'm in process of hooking up a new electric pump. I'm using a typical automotive relay with the driving circuit picks up the 5V from the electric fan pink/black wire then ground to chassis. The relay energized circuit connects to battery, goes thru relay, 15A fuse, pump motor then attaches to chassis ground. All connections been verified, battery hooked up and fuses checked.

Turn the key, then nothing happens. By passed relay or activated it with an external source, motor kicks in. Any suggestions?

:thud:
 

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Your probably not hooking the relay up right. There are numbers on the bottom of the relay next to the connections. #30 on relay goes straight to battery. #84 goes to ground. #85 goes to whatever you are using for a switch whether it be the ignition switch, toggle etc. This is your relay activation voltage.#86 and 86A are for the pump positive wire. Put it on #86 to come on when you activate your switch. If you put it on #86A, it will come on as soon as you connect it, and go off when you activate your switch. Connect the grond to the pump to the frame or engine ground.
 

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Discussion Starter #3
My relay has a #85-86 (activation side) with a #30, 87 and 87a (power side) on it. The relay portion measures 80 ohms or so.

On this relay it doesn't matter which side gets connected to the power or ground that energies the relay. I have proven this by placing a 9v battery in both +/- orientations, and the relay would then properly apply power to the motor.

Apparently, I'm missing my 12v when the ignition switch is thrown, verified with DVM.

More later, I gotta go to work to pay my fuel bill.
 

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My relay has a #85-86 (activation side) with a #30, 87 and 87a (power side) on it. The relay portion measures 80 ohms or so.

On this relay it doesn't matter which side gets connected to the power or ground that energies the relay. I have proven this by placing a 9v battery in both +/- orientations, and the relay would then properly apply power to the motor.

Apparently, I'm missing my 12v when the ignition switch is thrown, verified with DVM.

More later, I gotta go to work to pay my fuel bill.
Your right about the numbers. It had been awhile since I looked at one. And you are also right that it doesn't matter which way you connect the 85/86 poles as long as one is ground, and the other is hot with ignition switch on. #30 goes to Batt+. It sounds like you are missing the 12v from the ignition switch. #87 goes to pump positive wire. #87A works in reverse and would have it energized all the time until ignition switch is turned on. The turn signal fuse is a good source for your ignition line. They only come on when the key is in the forward position, and there is very rarely anything else tied into that same fuse. But I would take the fuse up one notch. Like a 10 to a 15, etc.
 

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Discussion Starter #5
So far luck. I'm starting to think that I must of broken the pink/black wire when I reinserted the bundle back into its plastic protective cover, for the electric cooling fan won't kick in now either. Previously I had hot wired those fans to a bypass switch for radiator cooling after autocrossing. Didn't have time to trace it down further tonight.

Snipped out my new relay feed, but it didn't help get the fan going either. Didn't have time to trace it down further tonight.

Good idea on using the flasher circuit. Never did like hooking to the pink/black wire for it looked marginal anyway with it being a #22.
The relay takes about 2W to drive. I know, I know it can take it, its just one of those seat of my pants thing.

Thought about inceasing the fuse too, but I was trying to find a 12.5W locally - to no avail. Guess I'll try the 15W. Thanks.
 
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