IC pump troubleshooting help...

R

RedlineRex

New member
Okay guys, I went thru the basic troubleshooting procedures diagnosing why my 1 yr old Jabsco pump isn't powering up. FYI, The pump relay is hotwired.
I check the fuse behind the alternator: 12VDC;Good
I disconnect the 2 pin connector for the pump, check voltage: 12VDC;Good.

So now it seems like the problem is the pump, right? Here's the part that stumped me...

I take the 9.6V battery out of my cordless drill and hook it up to the pump leads... powers up?!?!?! :eek:
Now I opt to reconnect the 12V power ... nothing... I check the voltage between the two leads and it doesn't measure any voltage when connected... WTF!?! As soon as I disconnect the pump, I get 12VDC again.
Okay, so I'm not exactly a whiz at electronics ... but why would the pump work when fed 9.6V and not 12V? Could it have something to do with the 9.6V being a floating ground while the 12V is chassis ground? Please help...
If it sounds like the pump took a crap, please let me know... Thanks!!
 
TurboTony

TurboTony

Active member
Check for a good ground at the pump connector.

Also use a real test light to check for power at the pump, a multimeter can lie to you. It may show 12 volts, but if the circut can't carry enough current to feed the load it won't work.

HTH

Tony
 
R

RedlineRex

New member
Tony - good info, I'll try that after work tonight. Do you see any problems if I ground the negative lead somewhere near the CCHE? --Paul
 
turbodog

turbodog

Donating Member
The general answer is that you have a high-resistance somewhere in the 12v wiring to the pump. With no current flow (with the voltmeter) you get 12v. But, when the motor tries to draw 1 amp, all that voltage is dropped in the unwanted resistance. Possible sources:
1. bad fuse. I've seen it before. try replacing it, even though it looks OK.
2. bad relay contacts. Unplug the relay. use a paperclip or short wire and jumper from the red wire connection in the relay socket to the orange one. (connector pin "B" to "D"). The CAC pump should come on. If not, probably the fuse or a break in the wiring. If it DOES come on, the relay is likely the culprit. Could just be a bad contact from relay to socket. Plug it back in and try it. No go? Then 'borrow' the fuel pump relay or the A/C relay and plug it into the CAC connector. They're interchangeable.
HTH!
 
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