Bosch relay 12v 30amp, with two 87s?

Bosch relay lables both 87 tabs as 87, and not 87 & 87a. Does this mean it has two nomally open tabs and no normally closed tab or that the lowest 87 is really an 87a?

The other night I cut the +12v wire to the fuel pump and verified that the car wouldn't run for more than 3 seconds without gas... amazing :)

So I couldn't finish the rest of the setup, but I squeezed on those connectors to either end of the cut wire so that I could connect them to the 87a and 30 tabs of the relay... this I assume would be the relay's normally closed state and should provide current through the relay without power the 85 and 86 tabs for the coil. I guess I was wrong, or maybe this relay doesn't work that way. It's got two 87 ports, neither has an 'a' after it and with my voltmeter I was able to verify 12volts getting to the 30 tab, but not comming out either of the 87 tabs.

When I requested type of relay at autozone I asked for a normally open relay, but learned through others and this site that these types of relays can be used either way based on how you use them either the 87a or 87 tab.

Any ideas? I tried both relays already, I read in another post that I could check the ohm reading between 30 and 87a and then 30 and 87 to see 0 and infinit respective to the coil's state. I'll check that tonight...

For now I cut off one of the connects shoved the wire into the other and squeezed down on the tip of the connect to hold it there temporarily, so at least I was able to get to work :)

Thanks for any help.

What you have is a regular SPST relay, which is usually 4-terminal. On yours there is simply an extra 5th terminal for normally-open. There is no 87a. The extra terminal is just to help you wire it, in case you need two things running off the same relay.

BTW, all Bosch relays should have a little schematic on its side, to verify. Hope that helps.

Another way of saying it... 87a only exists on SPDT relays. You have a SPST.

Only cost me $10 to learn from this mistake, I should feel lucky.

You're right, the diagram shows the two 87s connected with the coil not touching either of them in the unpowered state.

I would have thought SPDT would be the standard thing you'd get when asking for a relay at an autoparts store... guess I was wrong. Tonight I'll ask the same guy for a transmission and see if he just gives me one without asking what car it's for. :)

JasonL wrote:

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What you have is a regular SPST relay, which is usually 4-terminal. On yours there is simply an extra 5th terminal for normally-open. There is no 87a. The extra terminal is just to help you wire it, in case you need two things running off the same relay.

BTW, all Bosch relays should have a little schematic on its side, to verify. Hope that helps.

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