Is my relay bad?

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GEODAVKY
Posts: 91
Joined: Wed Nov 21, 2007 9:40 pm

Is my relay bad?

Post by GEODAVKY » Fri Jul 17, 2015 10:45 am

My car won't start. Here's what I've found and done. Cleaned the battery post and ground connection, took the "relay for circuits under ignition switch" off and cleaned all the terminals and filed the points. Reinstall and connect battery. Points close with nothing on and ignition off.
Open a door to make inter lights turn on--relay closes. Turn headlights on everything goes dead.
Turn ingition switch to on position and try to start then everything goes dead. Contact closes.

Any ideas?
1967 330 GT 2+2 8767
George Davidson

BobA
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Re: Is my relay bad?

Post by BobA » Fri Jul 17, 2015 2:43 pm

Hi George: If you have a mulit VOM meter, energise the relay with 12 volts and read the resistance across the relay contacts. Should be near zero. If there is a lot of resistance, the voltage will not be carried across the contacts. Bob

GEODAVKY
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Joined: Wed Nov 21, 2007 9:40 pm

Re: Is my relay bad?

Post by GEODAVKY » Fri Jul 17, 2015 2:47 pm

Thanks Bob--I'll go do that next. But should the contacts be making contact when the battery is attached and nothing is or any doors open?
1967 330 GT 2+2 8767
George Davidson

GEODAVKY
Posts: 91
Joined: Wed Nov 21, 2007 9:40 pm

Re: Is my relay bad?

Post by GEODAVKY » Fri Jul 17, 2015 3:30 pm

The lowest scale is 200 and the reading is .7
1967 330 GT 2+2 8767
George Davidson

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330GT
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Re: Is my relay bad?

Post by 330GT » Fri Jul 17, 2015 9:56 pm

GEODAVKY wrote:My... Turn headlights on everything goes dead.
Turn ingition switch to on position and try to start then everything goes dead. Contact closes.

Any ideas?
Still sounds like bad connections in the ground or power battery leads. I found that my battery terminals were so old that they would oxidize easily. They would work for light loads, but everything would die with a large load (like lights or starter). Simply twisting the terminals back and forth would usually get me back on the road. Recently I replaced both terminals and haven't had a problem again. It was impossible to use the standard wire brush battery tool to clean the oxide off. The only way was to use a round file inside the terminals to scrape down to clean lead. This would last anywhere from a couple of weeks to a couple of months and I would have to do it again. Of course, this would happen whenever I was already tight for time to drive the 330 somewhere.

Remember, the ground goes from the battery to the bottom battery frame and then to the block (usually a header stud. So all connections need to be cleaned. Similarly, the hot goes to the solenoid by the starter and that end could be the issue. Of course, that is a major problem to clean as it requires removing the rear header to get to it.

Usually it Is the connections by the battery due to the out gassing from the battery causing corrosion.
Regards, Kerry
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BobA
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Re: Is my relay bad?

Post by BobA » Sat Jul 18, 2015 4:08 pm

Geodavky: The purpose of a relay is to serve as a means of switching a larger load than the switch can handle. It does this by using 12 volts applied to the relay to close the heavier contacts which in turn carry a heavier load than the switch is rated to carry.

GEODAVKY
Posts: 91
Joined: Wed Nov 21, 2007 9:40 pm

Re: Is my relay bad?

Post by GEODAVKY » Sun Jul 19, 2015 1:10 am

Why would the relay be closing when the battery is connected. The ignition is off and there are no lights on or doors open?
1967 330 GT 2+2 8767
George Davidson

Jumprun
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Re: Is my relay bad?

Post by Jumprun » Sun Jul 19, 2015 1:35 am

Maybe it's a bad ignition switch allowing current to the relay thereby closing the contact.

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