Does anyone know if this part was used on any of the 89 c4's? Supposedly the #16061602 was only used on the 90 thru 92 models but I had to take mine out of my 89 drop top because the fan runs continually when the module is plugged in. Upon removal I found this part on the car and not the silver can switching transistor #12484912. I need to make sure I order the correct replacement or if this part and the original part are interchangeable? Thanks!

 

Through the years there were a couple of engineering changes and the part was NLA then reintroduced I believe and many/most if they needed bought whatever available and maybe modified the connector wiring to use what they could find. If you've had the car for a few years and it worked I would try to match what's "on the car" and worked.

There's maybe Cadillac, Buick & Olds modules that will work if you've access to the salvage yards. If you're buying NEW do it local with the understanding that if it's not a match you don't buy.

 

[QUOTE=WVZR-1;1589906778]Through the years there were a couple of engineering changes and the part was NLA then reintroduced I believe and many/most if they needed bought whatever available and maybe modified the connector wiring to use what they could find. If you've had the car for a few years and it worked I would try to match what's "on the car" and worked.

There's maybe Cadillac, Buick & Olds modules that will work if you've access to the salvage yards. If you're buying NEW do it local with the understanding that if it's not a match you don't buy.[/QUOT

Seems most of the vehicles that used that part have been recycled by now. But the modules are available on line and there is quite a price difference between the two types. The 16061602 is less money. I bought the car two years ago and noticed the module was unplugged at that time and discovered the problem when I connected it. I'm thinking of comparing the digital controls next, they may give me clue also.

 

16061602 is the correct blower control module for a 86-89 Corvette.

There appears to be some web-sites listing wrong cross reference part numbers for the blower control modules.

The blower control module used for 86-89 Corvettes powered the blower motor and was also used to engage the AC compressor clutch.

Starting in 1990 Corvettes the blower control module only powered the blower motor. The ECM or PCM was used to engage the AC compressor clutch.

I would assume the 90 and up modules used on the Corvette don't have the AC compressor clutch circuitry.

This is a picture of the blower control module from my 89.

 

[QUOTE=Hooked on Vettes;1589914340]16061602 is the correct blower control module for a 86-89 Corvette.

There appears to be some web-sites listing wrong cross reference part numbers for the blower control modules.

The blower control module used for 86-89 Corvettes powered the blower motor and was also used to engage the AC compressor clutch.

Starting in 1990 Corvettes the blower control module only powered the blower motor. The ECM or PCM was used to engage the AC compressor clutch.

I would assume the 90 and up modules used on the Corvette don't have the AC compressor clutch circuitry.
This is a picture of the blower control module from my 89.




Thanks for the info Hooked. I can finally put this part of the problem to bed but unfortunately while investigating the wiring harnesses feeding the module, I found either an error in the GM service manual wiring diagram or at the 4 pin female plug which has two wires reversed. In section 8A electrical diagnosis cell 66 pg 8A-67-01 at the bottom left of the wiring is reversed at pins"C" and "D" car has grn/yel at C2-D and blk at C2-C whereas the manual shows them swapped. Now I wonder which is correct? Could you check the plug on your 89 and see? Thank you.

 

An '87 FSM shows that the CAR is correct and the service module was the same. I can't dispute OR confirm your '89 FSM because I don't have one to check but I believe you "understand" the FSM.

Perhaps someone else with an '89 FSM will check and confirm. It might be interesting to have a couple '89 owners confirm the pin-out on their car.

Even the '90 & '91 C2 connectors show C as being "black".

What might be interesting is to compare the diagnostics that accompany that 8A section to see how they might compare to the pin-out. The programmer is different for '88 and '89 so who knows what's up. It might be interesting to compare maybe an '88 pin-out also on the car.

Interesting that you were that thorough in your inspections. I believe that some of the BMC modules that serviced multiple years had unused circuits and unused pins in some of the connector faces.

 

On a 89 C2 pin D Black wire is ground. C2 pin C Green/Yellow wire is request clutch signal.

On 90-96 C2 pin C Black wire is ground. C2 pin D is not used.

Appears the prior owner installed a late blower control module and
moved the Black wire from C2 pin D to C2 pin C which appears should get the
blower to work but I don't know if the the AC compressor clutch would work.

If the blower motor runs when the ignition key is turned On and you have no control
of the speed, verify the fuse mounted to the firewall inside a black relay type housing
isn't blown.

Usually if the blower control module is bad, the fan runs even with the ignition off.

Below diagram shows the C1 and C2 connector wires for a 89.

 

So the OP's first move might be to just re-pin his so long as the module number is a match to yours?

OR

maybe confirming that the pigtail isn't a cut/splice added in a service repair attempt by going deeper into the conduit looking for evidence.

This is from an '87 and C & D are reversed from what you mention for ALL '86 - '89 and since the programmer is different in '88 & '89 I thought that might be responsible for the change. The OP's car matches this '87 FSM excerpt.

 

For a 89 he needs to verify his wiring is like the diagram I posted if he is going to use the 16061602 module.

Here's a diagram for the 89 and 86 pin outs.
Notice C2 pins C and D are labeled different between these two years
but the actual control wires are wired the same. Only the alpha pin out lettering for the connector is different and possibly the color of the wires.

My guess would be connector C2 alpha pin outs for 86 and 87 are the same.Not sure about a 88 and 89-96 have C and D swapped. In the Original posters case if some one installed a 90-96 Blower control module in a 89 they would move pine C2 pin D to C2 pin C. This may get the blower to work but probably not the AC compressor since the AC clutch control was done by the ECM or PCM for 90-96 and not the Blower control module.

------------------------------------------------------------------------------------
Post what the C2 alpha pin out is on a 87.
------------------------------------------------------------------------------------

Not sure what the exact differences between the years on the older control heads are.
Firmware and how you get into diagnostic mode may be different. Some one did mention
getting in to the diagnostic model is a different button sequence from a coupe and a vert?

 

Here's from an '87 FSM and a '90 is identically orientated with the exception being that C1 "A" gets a cavity plug and C2 "D" get a cavity plug also. The '90 is C1 - 1 wire and C2 - 3 wire and I confirmed that on a car. The '87 is only an FSM (no car to confirm).




The '90 FSM uses the same 12052023 with C & D swapped from your image that shows the similar connector but NOT part #'d.

Your part #'d 12052023 in a '90 FSM is orientated just like your NON part #'d that mentions '89 - '96 BUT in a part #'d image C and D are swapped.

I had trouble putting my hands on the '90 FSM. Here's the '90 C1 & C2

Attachment 47895747

 

OP - I forgot that I actually have an '89 harness and the green/yellow is in the D cavity of the connector and of course black in C. Your car connector is correct when compared to this connector in an '89 harness that I actually have checked. My phone didn't snapshot it well and the camera is on loan. I'm referencing the CONNECTOR paying no attention to the FSM information or the images that we've posted. These are the molded letters on the connector.

 

Just what I was looking for. Having the harness verification that the pin out is correct on my car. Seems for those of us having a FSM for the 89 should make note that it is incorrect. I don't understand how the FSM became altered and incorrect but as they say seeing is believing and thanks to all you Vett Heads for participating in the conversation. Your knowledge and dedication to the Corvette world is so helpful and a valuable resource for us shade tree mechanics. Thank you all again...Leaps!

 

I'm accustomed to the pin-out of the connector matching the component but maybe in this particular case that isn't the situation. I don't have a BCM to check but I believe what you need to do is using the diagnostics in the FSM confirm it first hand.

The couple pages following the wiring diagram for diagnostics it would seem are very important to sort first hand. An '88 diagram is the same as an '89 from what I've been able to see but I have neither FSM to read the diagnostic aids and troubleshooting section.

 

This is a picture of the two connectors on a 89.

 

Well I now have fan speed control yeaaa! But even though the fan speeds up and slows down there is little or no increase or decrease in the volume of air flow from the vents. What is going on guys?

 

The c4's were never know to have a good volume of air coming from the vents.

Note: All air passes thru the evaporator core. The air then is deflected by the blend door. The temperature setting determines how much of the air passes thru the heater core or bypasses it.

Unplug the two pin connector at the blower motor.

Turn the ignition On.

Set blower speed to 10.
Measure the voltage at the Connector.
Purple wire is the voltage for the Blower motor and Black wire is ground.
Should be 11.8 or higher.
If you set the blower speed to 1 voltage should be around 4 volts.

This tells you the voltage sent from the AC Programmer is correct and
the Blower Control module is providing the proper voltage to the blower motor.

If the results are correct, remove the blower motor and manually spin the
squirrel cage. Should spin freely. You can also apply battery voltage the motor
and observe how well it spins.

Look inside the hole where the blower motor was.
Verify the Evaporator core is not clogged with dust and dirt.

If your complaint is the air is not coming out of the proper vents.

You need engine vacuum for the air deflection actuators to work. They direct the air
to the proper duct outlets. If you start the engine and select different air outlet positions and the air flow doesn't come out of the proper ducts could be the vacuum check valve located near the power brake booster area is bad. The vacuum check valve provides engine vacuum to the cruise control servo and the HVAC Programmer.

Here's a picture of an after market vacuum check valve. The factory one is all black and the shape is different. The check valve has a single input with two outputs.





Here's a thread that shows a clogged evaporator coil.

https://www.corvetteforum.com/forums...rator-out.html




Here's a picture of the duct work.

 

Thanks for the input. I am currently at the jersey shore and will perform the checks upon my return home. Fan speed does vary as control is actuated it just seems the volume does not. Also i am not sure if the deflection from defrost to heater etc is working correctly. I have already replaced the vacuum check valve some time ago. I will be in touch with results. ps the cruise control has not worked since I bought the car in 2013.

 

OK Hooked! My voltage readings were at setting 1=4.8v and at setting 10=12.4v. It then dawned on me what you said about the transfer of control from the heater to floor and defrost were vacuum controlled so after starting the engine and working the controls, all functions were working. I have what I consider to be very good air flow also, and am a happy camper. Thank you...leaps.

 

Does the cruise control work?