Long story short, I got a donor car to replace my 1997 XK8's tranny with an A drum failure with a different tranny. Knowing my heater pump wasn't working, I snagged the donor heater pump, replaced the brushes and gave to the tranny guy to put in. I do not think it is working.

My question is: how do you bench test electrical devices like this to tell if they work? Is hooking a battery charger up to the wires too much juice? Is there a way to supply just the right amount of voltage to determine if your soldering job inside the pump is good before you take the time to install?

If I can get this repaired, my install is now going to be much harder and I want to know it is going to work.

Brian

 

If you don't have a battery jumper pack or a spare battery, you could attach 2 wires to your battery ( power and ground respectively ) then touch the wires to pins on the pump and see if it goes.

 

I did attach the heater pump to a battery charger with jumper wires. I am not sure if that was a electric overload that melted the soldered wires from the new brushes.

I am asking if this is OK to do (hook wires up to battery/battery charger) or if you have to somehow limit the voltage.

B

 

You can plug it in on the car and see if it works - otherwise use a spare battery or the one in the car, you just need 12 volts to see if it comes on or not. I wouldn't use a battery charger for testing.

 

Easy way is to plug into the connector before plumbing ( with key off before running as it is a high current arcing hazard ) and hold tight as it will torque . This will ensure wire polarity as well . With a battery you risk arcing or shorting the pins with someone else holding the torquing motor . The electrical resistance of the motor will limit the current with a battery unless the motor is shorted internally . Battery charger depends on the chargers amperage as the motor is a somewhere 30 amp rating , a 5 amp setting will run slow as it is all it can supply . Replace the relay as the old pump may have damaged the power contacts inside .

 

All the above + don't get the polarity wrong. There's a diode across the positive and ground connections and it will not like being the wrong way round !!

 

Where is the relay that may need replacing? Maybe that is why the "fixed" pump isn't working.

You all must understand that where the heater pump is located does not make it easy to just plug back in and flip the switch.

Yes, I think a battery charger may have been overloading it.

I never thought of making sure polarity is correct also.

I just want to apply juice while it is out on my bench to make sure the motor purrs before i go through all the trouble of switching out with the non working motor.

B

 

Yes I understand the want for a bench test and the pigtail wire may be short as where it is installed . The charger won't overload it if as the motor has it's own wingdings resistance unless it has an internal short . Ensure to test it with say a 2 or 5 amp switch on the charger setting as you get your feel for it in probing the pins without touching the charger leads together . Then after you get a feel for it run the charger on the 50 amp setting ( if yours has one ) for true running power for a true run . Keep in mind possible arcing damage to the pins if that is what is there or put a paperclip if sockets . Going outside now to check on something else and will look at that motor side connector . The Yellow wire is the + and the Purple wire is the - .

The heater pump relay is in this pic for the marked washer pump for someone else : fuse box location fwd left engine