GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 Blazer - 4WD - RHD 🢒 Body and Accessories 🢒 Wiring Systems 🢒 Scan Tool Does Not Communicate with Heater and Air Conditioning (A/C) Control

Scan Tool Does Not Communicate with HVAC

Step

Action

Value(s)

Yes

No

1

Was the Data Link Communications System Check performed?

--

Go to Step 2

Refer to Data Link Communications System Check

2
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the scan tool from the Data Link Connector (DLC).
  3. Disconnect the electronic climate control  (ECC) module.
  4. Connect a DMM between terminal 2 of the DLC and terminal C11 of the ECC module.

Is there continuity present?

--

Go to Step 3

Go to Step 4

3

Replace the ECC module. Refer to Control Assembly Replacement .

Is the repair complete?

--

Refer to Data Link Communications System Check

--

4

Connect the DMM between terminal 2 of the DLC and splice S201.

Is there continuity present?

--

Go to Step 5

Go to Step 6

5

Connect the DMM between terminal 2 of the DLC and terminal C11 of the ECC module.

Is there continuity present?

--

Refer to Data Link Communications System Check

Go to Step 7

6

Locate and repair the open or cause of resistance in CKT 1807 (PPL) between the DLC and splice S201.

Is the repair complete?

--

Refer to Data Link Communications System Check

--

7

Locate and repair the open or cause of resistance in CKT 1807 (PPL) between terminal 2 of the DLC and terminal C11 of the ECC module.

Is the repair complete?

--

Refer to Data Link Communications System Check

--