[Dcairns560]

I am having a problem with my battery being completely drained over night. I have determined that my electric water pump circuit is drawing power all the time. I have it wired using a bosch style relay, and the pump is switched on and off via switch in the ground wire for the relay. I have tried another relay so I know that isnt the problem. I am assuming that I wired the circuit incorrectly.

I would greatly appreciate it if you could describe how the circuit is supposed to be wired, or better yet maybe post a schematic.

Thanks in advance!

[This message has been edited by Dcairns560 (edited 04-26-2001).]

 

[Coppertop]

Just give me a chance to draw it up

 

[Coppertop]

Sorry for the delay (darn school work and work on Saturdays

)

Here is what you described (well how it should be based on what you described):

Most people switch the (+) side of the coil to turn the relay off, but switching the ground is okay too. I'm assuming the ground switch may be some sort of thermostat type device that grounds out when the right temperature is reached?

NOTE If you are switching the ground side, where do you have the +12 volts side of the coil running to? This CAN make a big difference. For example, if you run that wire to something that always is "hot", and the temp sensor is grounded most of the time, the relay will engage, thus allowing the pump to draw on the battery and drain the battery. Most situations call for running the wire that feeds the "86" coil terminal to the IGN slot on the fuse box. This means the relay will only be allowed to turn on during the times the key is in the "on" position (engine running).

Also, how many amps is this pump rated for???
Typical relays can only handle about 30 amps. If it draws something like 25 amps, you really should run two relays in parallel like shown below (notice the ground is not switched--because I drew this for someone else a while back, the same basics apply):

Hope that helps.

 

[Dcairns560]

Thanks for taking the time to draw that out. It looks like I do have it wired just a little differently than you show, so hopefully that is the problem. How could I figure out how many amps that the pump draws? Call the manufacuturer I assume or is there a way you can figure it out? So I wont be able to check this out for a day or two. I will let you know what I find.

Thanks again!
I know what you mean about working weekends! I have to work tonight, and tomorrow

[This message has been edited by Dcairns560 (edited 04-28-2001).]