[sharvey]

In going over my new to me '92 164S, I was cleaning out the glove box and noticed what looked to be a plastic door on the left side, I popped it off and saw an unplugged connection. That's odd I thought, so I plugged it together and immediately heard a clicking noise in the dash. I unplugged it and started searching the board - bad stepper motors?

 

[144]

Maybe. Plug it back in and run the heat control from full hot to full cold and watch for the little arm on the stepper motor to move full throw.

Then run through all the vent positions making sure that the air comes out the appropriate vent. If it doesn't then the stepper gearbox could be bad, the distribution drum pivot broken, or both.

If you need a rebuilt stepper assembly, let me know.

 

[Alfajay]

That clicking is probably the stripped, plastic gears trying to move the heater and air distribution parts.

Well, maybe this is terrible news; I see you live in South Dakota and New York. Here in California, I have lived with a "clicking 164 for years". My heater control works OK, and the distribution drum plastic just disintegrated where the motor engages it. So I locked the drum in the "send air everywhere" position, and just momentarily plug in that connector in the spring and fall to switch between heat and no heat. Maybe it isn't that simple where you live.

 

[VeeSix]

It's just a bad stepper motor, probably been disconnected because the clicking noise gets so dam annoying, like previously mentioned disconnect the linkage and leave it in the best all round position, they can be replaced by removing a few dash parts.

 

[Spitfire]

Steve, I hope you caught mention of bad hvac controls in one of my emails. I hope this isn't a huge surprise for you.

 

[Alfajay]

... they can be replaced by removing a few dash parts.

Having done the job myself, I wouldn't call it "a few dash parts". More like the whole console and top of the dash. Not difficult, but tedious. There is a video of the procedure, as well as a step-by-step instruction, available online.

 

[Richard2]

Follow Roadtrips advice. If everything works, I'd just add the resistors without doing the stepper motors and hope for the best It's worth a try and much easier than replacing steppers.

 

[Del]

Take a look at this from pinino: http://www.alfabb.com/bb/forums/attachments/164-168-1991-1995/667425d1415745606-steppers-r-r-steppers_r_r.pdf

This should be of great help, rather than taking the dash apart otherwise.

Also this from roadtrip, as mentioned by Richard, for the details of changing the gears: http://www.alfabb.com/bb/forums/164-168-1991-1995/379737-164-stepper-motor-assembly-refurbishment.html

Many thanks for the work these guys have done in order to make life a little easier. Too bad this info wasn't around years ago.

 

[Michael Smith]

It's just a bad stepper motor, probably been disconnected because the clicking noise gets so dam annoying, like previously mentioned disconnect the linkage and leave it in the best all round position, they can be replaced by removing a few dash parts.

LHD models require a bit more work than that!

Odd that the steppers are bad in this car since they tended to break a few days after the warranty ran out. That is no doubt why the connector was unplugged.

BTW, I think all 92 164 were actually just leftover 91, sales were so low.

 

[sharvey]

John I'm not surprised at all, you did tell me about the HVAC in your excellent review of the car. As I have been sorting things out I was curious how I would find out they, the steppers were bad.
I have cleaned and refreshed every window and seat switch, rebuilt the overhead console, repaired the bulkheads, shampooed the carpet, replaced the stereo system and cleaned and treated the seats. This is a fun car to work on, the steppers will have to wait until I get the flashing airbag light fixed.

 

[144]

The Airbag is fairly easy to figure out. Extract the fault code from the system using a couple leads and a on-off switch. I made one out of a couple lengths of small wire with small female spade ends and a SPST switch. You'll connect that to the Airbag test connector lead. That is just half a connector (male half) located hanging down from the under dashboard down into the far right side kick panel of the passenger seat.

Be real careful about working around the airbag/squib, not to introduce any current to it.

Several good threads on the BB already on diagnosing airbag faults. Do a search.

****************

Here's a customized synopsis of the TSB for getting the codes.


TO EXTRACT FAULT CODES FROM THE MEMORY

1. Locate the airbag test connector (4 wires) under the right side of the dashboard.

2. Connect your switch to the blue/black and black wires.

3. Turn on the ignition key.

4. Observe the AIRBAG warning light; it will flash once, followed by a short pause, then flash twice. This represents code 12, which is an indication that the troubleshooting procedure is "running". Code 12 will be repeated 3 times.
(Example: 12-12-12)

5. If fault codes are stored, they will follow the code 12 sequence and the AIRBAG warning light will flash a 2-digit fault code 3 times for each fault indication stored in the memory. (Example: 26-26-26)

6. When the fault memory is empty, the AIRBAG warning light will again flash code 12-12-12 to indicate that all of the stored fault codes have been displayed.

Here are the possible fault codes you could get:

14 Forward left hand sensor grounded to chassis
15 Open circuit on forward left hand sensor
16 Failure to forward left hand sensor
24 Forward right hand sensor grounded to chassis
25 Open circuit on forward right hand sensor
26 Failure to forward right hand sensor
31 Current leakage to battery
32 Current shorted to battery voltage
33 Current leakage to ground
34 Current shorted to ground
35 Open circuit
36 Faulty squib
41 Short to ground/battery-warning lamp
42 Failure of air bag warning lamp
51 Faulty diagnostic unit

Often times an open sensor code can be cleared by disconnecting, spray with electrical cleaner, and reconnecting the two bright orange connectors located behind the passenger's LEFT (center console) kickpanel. Mine does this about once a year or so. I clean it reconnect and it's good. The ECU is very sensitive to minor electrical anomalies.

A 35 code is billed as "Open Circuit" but can also be a bad Airbag itself ("squib") rather than a 36 Faulty Squib. The way to test this is to disconnect the airbag and substitute a 2 ohm resistor to the clock spring wire. If the code clears, then you've got a bad Airbag itself. If not, it could be a bad connector, wire, or clock spring unit.

**********************

TO CLEAR FAULT CODES AFTER REPAIR:

Carry out the procedure outlined above to view all stored fault codes. Set your watch somewhere where you can see the second hand easily.

When the fault memory is exhausted, and the AIRBAG warning light is flashing 12-12-12 again (indicating "end of codes"),

Turn your test switch OFF for 3 seconds, then ON for 3 seconds, then OFF and quickly turn the ignition key to OFF. Be as accurate as possible on the times, hence the need to see the second hand on your watch.

Wait 15+ seconds, then turn on the ignition key to allow the airbag ECU to test the system. If there are no faults present, the AIRBAG warning light will come on with the key, then go off after 5-8 seconds, and remain off. If there are still faults present in the system, the AIRBAG warning light will come on with the key, go off after 5-8 seconds, then begin flashing again. If the AIRBAG warning light begins to flash immediately after turning on the ignition key, the previous fault codes HAVE NOT BEEN CLEARED.

If the AIRBAG warning light flashes again indicating that there are one or more faults present in the system, extract the fault code(s), repair the fault(s), and clear the fault memory again.