One transistor and two diodes............problem solved.
Now all I need is a suitable replacement transistor cuz I stole one from one of the vacuum circuits.
Anybody know the specs?
Blend Door is KILLING ME!
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Those are mystery GM part numbers. Unfortunately there is no cross reference to standard part numbers. Generally they leave off the first four numbers and your 8399 is probably something like 16038399. I've seen parts like this available on Chinese web sites, but you'd have to buy a whole reel with 2000 - 3000 parts.
I think those parts are pretty generic and you should be OK with a 2N2222, which is rated at 40V, 800mA.
[EDIT] I calculated the power dissipated by the 140 ohm resistors. The equation is V*V/R. At 13 volts that comes out to 13*13/140 = 1.2 watts. No wonder they overheat. They are rated at 1 watt. The rule of thumb is to double the resistor power, so they should be at least 2 watt resistors. [/EDIT]
I think those parts are pretty generic and you should be OK with a 2N2222, which is rated at 40V, 800mA.
[EDIT] I calculated the power dissipated by the 140 ohm resistors. The equation is V*V/R. At 13 volts that comes out to 13*13/140 = 1.2 watts. No wonder they overheat. They are rated at 1 watt. The rule of thumb is to double the resistor power, so they should be at least 2 watt resistors. [/EDIT]
Last edited by Cliff Harris; Aug 31, 2013 at 06:11 PM. Reason: Added note on resistor dissipation.
Thread Starter
Cruising
Joined: Aug 2013
Posts: 14
Likes: 0
From: DeMotte IN
Those are mystery GM part numbers. Unfortunately there is no cross reference to standard part numbers. Generally they leave off the first four numbers and your 8399 is probably something like 16038399. I've seen parts like this available on Chinese web sites, but you'd have to buy a whole reel with 2000 - 3000 parts.
I think those parts are pretty generic and you should be OK with a 2N2222, which is rated at 40V, 800mA.
[EDIT] I calculated the power dissipated by the 140 ohm resistors. The equation is V*V/R. At 13 volts that comes out to 13*13/140 = 1.2 watts. No wonder they overheat. They are rated at 1 watt. The rule of thumb is to double the resistor power, so they should be at least 2 watt resistors. [/EDIT]
I think those parts are pretty generic and you should be OK with a 2N2222, which is rated at 40V, 800mA.
[EDIT] I calculated the power dissipated by the 140 ohm resistors. The equation is V*V/R. At 13 volts that comes out to 13*13/140 = 1.2 watts. No wonder they overheat. They are rated at 1 watt. The rule of thumb is to double the resistor power, so they should be at least 2 watt resistors. [/EDIT]
Cliff, thank you again for all of your help. With the right information and a little common sense, anything is possible.
Racer
Joined: Sep 2010
Posts: 305
Likes: 2
From: Epfenbach BW
Just had the same problem, heat stuck full on.
Checked the transistors and they were the problem.
I only had 2N3904 which are rated at 200mA but they worked fine. Will get some 2N2222 to be on the safe side though!
I swapped 2 original transistors from the solenoids and used them for the blend door actuator. The solenoids most likely draw less current ao 2N3904 will work as a test.
Great thread, I would have never gotten such a fast and easy solution!
Thanks
Checked the transistors and they were the problem.
I only had 2N3904 which are rated at 200mA but they worked fine. Will get some 2N2222 to be on the safe side though!
I swapped 2 original transistors from the solenoids and used them for the blend door actuator. The solenoids most likely draw less current ao 2N3904 will work as a test.
Great thread, I would have never gotten such a fast and easy solution!
Thanks
Last edited by eaglevision993; Jul 22, 2014 at 05:09 PM.
Instructor
Joined: Apr 2013
Posts: 219
Likes: 1
From: Toronto Ontario
Just had the same problem, heat stuck full on.
Checked the transistors and they were the problem.
I only had 2N3904 which are rated at 200mA but they worked fine. Will get some 2N2222 to be on the safe side though!
I swapped 2 original transistors from the solenoids and used them for the blend door actuator. The solenoids most likely draw less current ao 2N3904 will work as a test.
Great thread, I would have never gotten such a fast and easy solution!
Thanks
Checked the transistors and they were the problem.
I only had 2N3904 which are rated at 200mA but they worked fine. Will get some 2N2222 to be on the safe side though!
I swapped 2 original transistors from the solenoids and used them for the blend door actuator. The solenoids most likely draw less current ao 2N3904 will work as a test.
Great thread, I would have never gotten such a fast and easy solution!
Thanks
But wa\hat are transistors ,where do I buy some, where on the car are they?
My a/c unit is a blank scene and nothing works.I am boiling to death in there.Help!
Ok,
Racer
Joined: Sep 2010
Posts: 305
Likes: 2
From: Epfenbach BW
Hi,
the transistors which were bad in my case are located inside the HVAC programmer underneath the driver side dash. Not the a/c controller with the display.
Transistors basically work like small relays. They switch higher current with a low current signal. Every electronic store has them. Here is what they look like:
http://mic.hit-karlsruhe.de/projekte...transistor.jpg
If you remove the programmer, also replace the big capacitor and the 2 140 ohm resistors. Then reflow all soldering points on the board for good measure.
But a blank display may be a different fault. There are tons of reading material here on non working a/c head units. Most problems are caused by the connection between the mainboard and display board inside the unit.
Best regards
Benjamin
the transistors which were bad in my case are located inside the HVAC programmer underneath the driver side dash. Not the a/c controller with the display.
Transistors basically work like small relays. They switch higher current with a low current signal. Every electronic store has them. Here is what they look like:
http://mic.hit-karlsruhe.de/projekte...transistor.jpg
If you remove the programmer, also replace the big capacitor and the 2 140 ohm resistors. Then reflow all soldering points on the board for good measure.
But a blank display may be a different fault. There are tons of reading material here on non working a/c head units. Most problems are caused by the connection between the mainboard and display board inside the unit.
Best regards
Benjamin
Instructor
Joined: Apr 2013
Posts: 219
Likes: 1
From: Toronto Ontario
The unit is a box, they just tell me to buy a new box.
How would a non handy person fix this?
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Find a handy person. A Corvette club in your area might have one. I can't really help you with this. I've been doing electronics for over 50 years and I can do almost anything so it's kind of hard for me to relate to someone who has no experience at all.
Racer
Joined: Sep 2010
Posts: 305
Likes: 2
From: Epfenbach BW
If you find someone with even medium electronic knowledge he will be able to replace those transistors and related components.
Just show him this page and if he knows his way around basic electronics he will immediately know what to do. The transistors can be bough at any Radio Shack or similar store.
Just tell them you need 2 140 Ohm / 3 Watt /5% resistors and around ten 2N2222 NPN-transistors or equivalent. They are just a couple of cents each...around 50 cents and 10 will be almost twice as much as you will need for the whole box.
The procedure of replacing the transistors is easy, but you need basic solering skills. Resistors tolerate too much soldering heat, but transistors may be damaged so you need to know how to solder. There are tons of online tutorials on soldering and transistor replacement. It is really not hard at all.
But if you feel more comfortable giving the job to an experienced person, any one who works with electronics can do it. TV/radio repair shops for example.
Best regards
Benjamin
Just show him this page and if he knows his way around basic electronics he will immediately know what to do. The transistors can be bough at any Radio Shack or similar store.
Just tell them you need 2 140 Ohm / 3 Watt /5% resistors and around ten 2N2222 NPN-transistors or equivalent. They are just a couple of cents each...around 50 cents and 10 will be almost twice as much as you will need for the whole box.
The procedure of replacing the transistors is easy, but you need basic solering skills. Resistors tolerate too much soldering heat, but transistors may be damaged so you need to know how to solder. There are tons of online tutorials on soldering and transistor replacement. It is really not hard at all.
But if you feel more comfortable giving the job to an experienced person, any one who works with electronics can do it. TV/radio repair shops for example.
Best regards
Benjamin
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski