tssteph

Anyone work for GM that can tell me what turns the electric water pump on that circulates water through the heater core on a 2000 Venture van? I have searched the net for information and can not find anything. The van has no heat unless the engine is about 1500 rpm, found the pump on the inner fender but it has no power going to it.

Thanks, yea I know this isn't vansonly.com but there seems to be a lot of expertise on this list.

Vmax

Check that you have enough antifreeze. The 3.4 has two piece intake. Gasket goes leaks antifreeze into cylinder fluid level drops no heat. Engine will sound like lifter noise on cold stars. It is putting antifreeze into intake. Snif exhaust on start lots of condensation and antifreeze smell. I know 3 other people who have experienced it. Fix it quick. 700 dollars at dealer or use can of head gasket sealer drain flush, run with sealer till hot, drain, let set over night, flush then fill with antifreeze. Will take about 3 hours but it works.

No electric pump manual water pump passenger side of motor.

cartman

Yes vmax you are correct the plastic intake gaskets crack and leak. if you pull Your oil fill cap and there is a white/tan cheesey substance it is certainly leaking get it repaired immediately! by the time you see it in the oil it's too late. also there is no electric pump.

tssteph

Well then the van I worked on is different then every other Venture van out there. There is a two wire rubber mounted water auxillary water pump mounted on the drivers side inner fender on the strut tower. This is a factory mounted/installed pump. It has a heater hose inlet and outlet , if I take these hoses off and start the car very little water comes through the hose, if I rev it up a lot of water goes through the hose. Hence the reason that they only have heat when the engine is reved up. Even the heater hoses are marked to say "To pump" and "From pump".

Vmax

My 97 Trans Port did not have one. This is probably your source from service bulletin.
Auxiliary Coolant Bypass Pump Switch Replacement

Turn the ignition OFF.
Open the hood.
Disconnect the electrical connector from the auxiliary coolant pump bypass switch.
Unclip the switch from the back side of the front bumper beam.
Remove the switch from the vehicle.
Installation Procedure




Install the auxiliary coolant pump bypass switch to the vehicle.
Clip the switch to the back side of the front bumper beam.
Connect the electrical connector to the switch.
Close the hood.

tssteph

I knew someone on the lsit would come through... THANKS.

tssteph

Ok, I am stuck again. The local GM dealership does not know what to look for. They found the pump but no switch. What bulletin are you looking at?

Thanks
Brian

Vmax

More info switch only operates 36 to 47 degrees. Chances are you are trying to fix something that is not broke. Here is full info.
Heating Insufficient - Auxiliary
Insufficient Heating of the Rear Seat Area
Inspect for one of the following conditions:

Inspect for a faulty auxiliary coolant bypass pump and auxiliary coolant bypass pump switch.
A faulty blower motor. Replace a faulty blower motor.
A faulty blower circuit. Repair or replace faulty wires or connections.
Inspect for the incorrect operation of the controls. Advise the driver to use high blower speed in order to force air into the rear of the passenger compartment.
Inspect for an obstruction on the floor. Inspect for the following conditions under the front seat:
Bulky objects.
Torn insulation.
Insufficient Heating
Inspect the duct work for the following conditions:
The proper insulation.
Obstructions.
Inspect the blower operation.
Inspect the following components for the proper installation and the proper operation:
The temperature lever.
The temperature motor.
Circuit Description
The auxiliary coolant bypass pump provides additional coolant flow for the heater core. The operating temperature range of the auxiliary coolant bypass pump is between 2°C (36°F) and 8°C (47°F). The auxiliary coolant bypass pump is powered by ignition voltage through the auxiliary coolant bypass pump switch. The ground is provided by the ground circuit.

Test Description
The numbers below refer to the step numbers on the diagnostic table.

The auxiliary coolant bypass pump operates only between 2°C (36°F) and 8°C (47°F).

Step
Action
Yes
No

Schematic Reference : HVAC Compressor Control Schematics in HVAC Manual.

DEFINITION: The auxiliary coolant bypass pump is inoperative.

1
Did you perform the HVAC Diagnostic System Check?
Go to Step 2
Go to Diagnostic System Check

2

Important
For auxiliary coolant bypass pump operation, the ambient air temperature must be between 2°C (36°F) and 8°C (47°F).


Turn ON the ignition with the engine OFF.

Does the auxiliary coolant bypass pump operate?
Go to Testing for Intermittent and Poor Connections in Wiring Systems
Go to Step 3

3
Disconnect the auxiliary coolant bypass pump.
Probe the auxiliary coolant bypass pump control circuit of the auxiliary coolant bypass pump with a test lamp that is connected to a good ground.
Does the test lamp illuminate?
Go to Step 4
Go to Step 5

4
Probe the auxiliary coolant bypass pump control circuit of the auxiliary coolant bypass pump with a test lamp that is connected to the ground circuit of the auxiliary coolant bypass pump.

Does the test lamp illuminate?
Go to Step 6
Go to Step 7

5
Disconnect the auxiliary coolant bypass pump switch.
Probe the ignition 1 voltage circuit of the auxiliary coolant bypass pump switch with a test lamp that is connected to a good ground.
Does the test lamp illuminate?
Go to Step 10
Go to Step 8

6
Connect the auxiliary coolant bypass pump.
Connect a 10 amp fused jumper between the ignition 1 voltage circuit and the auxiliary coolant bypass pump control circuit of the auxiliary coolant bypass switch.
Does the auxiliary coolant bypass pump operate?
Go to Step 13
Go to Step 9

7
Repair the ground circuit of the auxiliary coolant bypass pump. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?
Go to Step 14
--

8
Repair the Ignition 1 voltage circuit of the auxiliary coolant bypass pump switch. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?
Go to Step 14
--

9
Repair auxiliary coolant bypass pump control circuit of the auxiliary coolant bypass pump. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?
Go to Step 14
--

10
Inspect for poor connections at the harness connector of the auxiliary coolant bypass pump. Refer to Testing for Intermittent and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?
Go to Step 14
Go to Step 12

11
Inspect for poor connections at the harness connector of the auxiliary coolant bypass pump switch. Refer to Testing for Intermittent and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?
Go to Step 14
Go to Step 13

12
Replace the auxiliary coolant bypass pump. Refer to Auxiliary Coolant Pump Replacement .

Did you complete the replacement?
Go to Step 14
--

13
Replace the auxiliary coolant bypass pump switch. Refer to Auxiliary Coolant Bypass Pump Switch Replacement .

Did you complete the replacement?
Go to Step 14
--

14
Operate the system in order to verify the repair.

Did you correct the condition?
System OK
Go to Step 3



--------------------------------------------------------------------------------

Vmax

Document ID# 794756
2000 Chevrolet/Geo Venture Ext for info on switch

cartman

Isn't that pump just for the rear heat, should not effect front heater core flow