QuestionQUESTION: Have 99 gmc suburban. Heated seats wont work. fuses are fine. What else/where else should i be checking? They weren't working when i bought from prior owner, and he only noted that a shop told him it was an $800 problem, so he didnt pursue.
Thanks for the help.
ANSWER: Hi
It's a pretty long diagnostic procedure for inop front heated seats.
If you'd like the diagnostic worksheet, please follow post back and I'll send it to you.
Remember it is VERY deatiled, so if you do not have auto electrical experience... you may want to take it and have it re-diagnosed.
There is numerous items and wiring it could be.
Pawl
---------- FOLLOW-UP ----------
QUESTION: I have a neighbor who is an industrial electrician. He reads those like i read the Sunday comics. Yes, please send!
Thanks again!
AnswerHi
Here is diagnostics....
I have no way of sending schematics, but you can click the private box, and I can then email them to you.
Heated Seat Inoperative
Step
Action
Values
Yes
No
Schematic Reference: Heated Seats Schematics
DEFINITION: One or both of the front heated seats are inoperative.
1
Has the Heated Seats System Check been performed?
--
Go to Step 2
Go to Heated Seats System Check
2
Is the front passenger seat heater inoperative in the high and low modes?
--
Go to Step 3
Go to Step 4
3
Disconnect the passenger seat belt buckle switch connector C228.
Turn ON the ignition.
Operate the front passenger heated seat switch in the high and low modes.
Does the front passenger heated seat operate in the high and low modes?
--
Go to Step 25
Go to Step 4
4
Disconnect the heated seat module.
Connect a test lamp from the harness connector terminal D to a good ground.
Does the test lamp illuminate?
--
Go to Step 5
Go to Step 17
5
Connect a test lamp from the heated seat module harness connector terminal D to terminal F.
Does the test lamp illuminate?
--
Go to Step 6
Go to Step 18
6
Connect a test lamp from the heated seat module harness connector terminal C to ground.
Turn ON the ignition.
Operate the heated seat switch in the high and low switch positions.
Does the test lamp illuminate in the high and low switch positions?
--
Go to Step 7
Go to Step 10
7
Turn OFF the ignition.
Using a DMM measure the resistance through the heated seat switch from the heated seat module harness connector terminals C to B.
Operate the heated seat switch in the high and low switch positions.
Is the resistance at or near the specified values?
• High 496 ohms
• Low 275 ohms
Go to Step 8
Go to Step 20
8
Using a DMM measure the resistance through the heated seat elements from the heated seat module harness connector terminals A to F.
Is the resistance within the specified values?
1-5 ohms
Go to Step 9
Go to Step 11
9
Using a DMM measure the resistance through the heated seat cushion temperature sensor from the heated seat module harness connector terminals E to F.
Is the resistance within the specified values?
5 k-15 k ohms
Go to Step 26
Go to Step 15
10
Disconnect the heated seat switch connector.
Connect a test lamp from the harness connector terminal D to ground.
Turn ON the ignition.
Does the test lamp illuminate?
--
Go to Step 19
Go to Step 21
11
Connect the heated seat module connector.
Turn ON the ignition.
Operate the heated seat switch to the high position.
Using a test lamp connected to ground back probe the seat cushion element 4-way connector terminal A.
Does the test lamp illuminate?
--
Go to Step 12
Go to Step 22
12
With the ignition ON and the heated seat switch in the high mode, back probe the seat cushion element 4-way connector terminal B with a test lamp connected to ground.
Does the test lamp illuminate?
--
Go to Step 13
Go to Step 27
13
With the ignition ON and the heated seat switch in the high mode, back probe the seat back element 2-way connector terminal A with a test lamp connected to ground.
Does the test lamp illuminate?
--
Go to Step 14
Go to Step 23
14
With the ignition ON and the heated seat switch in the high mode, back probe the seat back element 2-way connector terminal B with a test lamp connected to ground.
Does the test lamp illuminate?
--
Go to Step 24
Go to Step 28
15
Disconnect the seat cushion element 4-way connector.
Test circuit 182 for an open or short to ground. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Heated Seats System Check
Go to Step 16
16
Test circuit 150 from the seat cushion element 4-way connector to the heated seat module connector for an open. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Heated Seats System Check
Go to Step 27
17
Repair circuit 1840 for an open or short to ground. Refer to Wiring Repairs in Wiring Systems.
Is the repair complete?
--
Go to Heated Seats System Check
--
18
Repair circuit 150 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.
Is the repair complete?
--
Go to Heated Seats System Check
--
19
Test circuit 1503 for an open or short to ground. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Heated Seats System Check
Go to Step 29
20
Test circuit 1505 for an open or short to ground. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Heated Seats System Check
Go to Step 29
21
Repair circuit 341 for an open or short to ground. Refer to Wiring Repairs in Wiring Systems.
Is the repair complete?
--
Go to Heated Seats System Check
--
22
Repair circuit 1462 for an open or short to ground. Refer to Wiring Repairs in Wiring Systems.
Is the repair complete?
--
Go to Heated Seats System Check
--
23
Repair circuit 1985 for an open or short to ground. Refer to Wiring Repairs in Wiring Systems.
Is the repair complete?
--
Go to Heated Seats System Check
--
24
Repair circuit 150 from the seat back element 2-way connector to the heated seat module connector for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.
Is the repair complete?
--
Go to Heated Seats System Check
--
25
Replace the front passenger seat belt switch. Refer to Front Seat Belt Replacement .
Is the repair complete?
--
Go to Heated Seats System Check
--
26
Replace the heated seat module. Refer to Heater Module Replacement .
Is the repair complete?
--
Go to Heated Seats System Check
--
27
Replace the seat cushion heater element. Refer to Driver Seat Cushion Heater and Passenger Seat Cushion Heater Replacement .
Is the repair complete?
--
Go to Heated Seats System Check
--
28
Replace the seat back heater element. Refer to Driver Seat Back Cushion Heater and Passenger Seat Back Cushion Heater Replacement
Is the repair complete?
--
Go to Heated Seats System Check
--
29
Replace the heated seat switch. Refer to Front Seat Heater Switch Replacement .
Is the repair complete?
--
Go to Heated Seats System Check
--
