Hi all, so minor problem hit me, the LED display for the vent control has stopped working. The switch itself seems to work fine, air flow is redirected just fine but no little yellow lights. First thought was to try the adjustment procedure with no joy, they would never come on. Does anyone know if there is a way to repair or have the connector pin info so that I can check voltage? Thanks, Lester .. oh yeah, TRutlands has them listed at $ 1200.. hate to buy one only to find it's a simple loose wire.. ok, so I would hate to have to buy one.
Lester, If you find any information on this let me know also. I've searched an couldn't fine any information on these switches.
Hello is my first post I'm eulogio live in Spain and I have a 328, follow this forum long time ago, but due to problems with language participated a little. Well I have the same problem with mi switch and the solution was I think easy more than buy a new controller, ok first dismantel the swith there is many post for this, unplug the switch and open it four screw see picture, then conect again for measure the volt , see the picture first check the regulator 7805 ,volts in each pin if this is correct pass the next check , the controler of the led lm3914n check the pin 3 again , if there is 5 volts and the led is off the lm is bad desoldering and change in spain price of the lm 0.90 cent , and that is all, of course this solution is only for switch that work but the led do not work, in my case the regulator was the problem change it and the switch on the road again price of this component 0.35 cent , I hope this help with your problem, sorry for my bad english. Also I put the sheet of the component 7805 and lm3914n. Regards from spain. P.D.I can´t put in good order the picture but I think is easy for understand it Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Excellent write-up Eulogio! You must have been reading "The Art of Electronics." This book is a great source for repairing most of the 308/328 80's electronics. It's easy to repair since soldering/desoldering is large enough for an amateur.
Well rats. I checked the regulator and got 5V I checked both of the controllers and both have 5V at pin 3 but as the lights don't work then one of them is bad. This leads to the important question: Should I buy a pack of 10 knowing that other folk are sitting on bad switches? They cost $2.15 each and shipping is likely more than that. $ 5.23 USPS Priority mail. What do you think? Lester
Thanks for the comment robz, I like electronics and investigate, and these cars are good for this, I am a faithful follower of your Robzwork. Well I think that is very difficult to become to break this component,the murphy laws are there but it is not much money buy ten and have spare. the last chequed ,reviewed all welds of the lm3914,check when push the switch in pin 5 has 5 volts more or less to ensure that signal comes if this point is correct , I think replace the Lm, in my opinion desoldering the component and solder first a socket for this component , there is enought space for this in the switch case for replace more easy in the future . Image Unavailable, Please Login
Does anyone know where to get one of the 4 switches on the board. One of my switches seems to be a problem on my unit. Three of the switches work great and one is very touch & go.
The socket is a good idea, but may be a tight fit, especially next to the other pads. If there is a longer terminal version, you may have some flexibility to install. Good luck.
If intermittent, it likely needs cleaning and exercising. I use 91% rubbing alcohol and a solder brush and Q-tips for cleaning. Sometimes a little oil (3in1) may help. The switch does look conventional. Try Digi-Key/Radio Shack.
Eulogio, I edited you message for easier reading in English and thank you again! I agree, solder in a socket first but for another reason, too much heat on the chip can cause a problem so solder in the socket and IT takes all the heat. I now have ten of those on the way as well.. If it all works I ll let everyone know. Lester
Best first post ever in the history of F-Chat !! Welcome, and please do not be shy about posting more !!
Jeez, I've had my 328 four years and still trying to figure out how to turn the heat on! This was some post...thanks and welcome.
Yes Robz328 , is correct also you can put other socket Pin turned SIL wire wrap Thanks a lot Lester for your help, is correct the heat is bad for this circuit. there is a other kind of socket called SIL ( singel in line ) wire wrap is more easy to soldering, I think ,see a picture.the terminal of this pin is more longer, you need two of 9 pin for this the distance between pin is 2.54 mm standar for Ic, ebay source Turned Pin Wire Wrap SIL Socket 20 Pin | eBay Thank you for your comment I will try to keep posting Image Unavailable, Please Login
I have another question Eulogio, which of the IC's serve which set of LEDs? My luck would be that I carefully unsolder the working one! Thanks again, Lester
Hi Lester good question, I don´t remenber this point, but for check this, with the switch connected and the led off, vent and heat, in the LM, pin 1 , 10 to 18 ,see chart of lm3914, should have 0 volts in both Ic, now turn on both, vent and heat ,the red led should be on and yellow off , check pin 1,10 to 18 in both Ic ,one of them Ic should have 5 volts more or less , this is good and the other should have 0 volts, is bad. I hope tis help you, is dificult for mi explain in english sorry, anyway if you have any question please tell me, I try to help you. Regards Eulogio
Got it, just to help others; With the switch connected, turn on ignition, advance both vent and heat buttons then measure along pins of IC for voltage on the side opposite (Pins 10 - 18),from where the 5v measurement was taken in the earlier post, the IC that has no voltage is the one connected to the non-illuminating LEDs. Simple and thanks again Eulogio! Lester
ARRGGGGGHHHHHHH!!! Just finished a 3 hour marathon trying to unsolder and solder in the base and the chip. I can NOT get the solder out of the holes and it's driving me nuts. Tomorrow I'm going to try a small drill bit to make the holes larger and cleaner. The good news is that I have not made the switch worse. Measuring the voltage along the far side I get 3.4 v or so on both chips (new and the one I did not work on). Still same problem, vent control lights up, heater control doesn't. Anything else that I can measure Eulogio? Lester
Use "solder wick" from RadioShack or equivalent. It is flux soaked copper braid. Put it on top of hole, put iron on braid and when solder shows on braid in 5 seconds or so, stop and remove braid. If solder not removed fully, move to clean spot in braid and repeat. Be sure to wait a minute or two to allow some cooling between spots so you do not cause damage such as de-lamination or burning of the board. It may take 2 or 3 spots of braid but that is ok. Go slow and avoid damage. Good luck and I hope this helped.
Hi lester I am sorry for hear this, well give me time to look at the scheme, and tell you that measure, please don't try this "Tomorrow I'm going to try a small drill bit to make the holes larger and cleaner." is very easy that you break the circuit panel for clean de holes use a desoldering pump or desoldering braid and a ton of patience. Please wait , I will response as far as posible. regards Eulogio
Use solder wick as described. Practice on something else first (a old electronic toy, etc. with separable components) until you get the hang of it. Also, clean a lot and use flux.
Hi lester, first sorry for the delay, I am very busy in this days . Well ,I don`t know if the switch is right or left, anyway I prepare for both switch a little diagram I suppose the switch is in place now but the light don`t work, first try to calibration procedure service bulletin 80-36, well if this don`t work . Measure the volt between pin 5-2 the signal will be a few volts 0-5 volts , then push the switch for change the vent position the volts in pin 5 should change because the variable resistor in the motor return the signal depend of the posicion the flaps or heater valve, see scheme, could be failure of this variable resistor, if this resistor don`t work the lm 3914 never turn on the led. Lester, if you have 3.4 volts in both lm the light shou have off in both circuit is this correct? I forgot tell you the logical in this circuit is negative when the led is on the corespondeng pin will be ground. The picture show only the vent motor, the heater motor is in the scheme number 103 and 11, the operation of this is the same. The first picture right switch and the second left. Try this and after tell me what happend. Please traslate for better understanding if you see something bad, thanks Regards. Eulogio Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Just to make sure, I am measuring voltage at the red arrow (Pin 3 and vehicle ground) and voltage change between the yellow arrows (Pin 2 and pin 5) . Which pin should I be using as the ground of these two? Thanks again Eulogio! Lester Image Unavailable, Please Login
.. and how would I check the potentiometers? Accidentally I verified LED operation as I shorted across pin 1 and pin 2 which lit up bottom yellow LED... Lastly, which wires at the plug could I measure across to verify change in resistance with the motor variable resistor? Lester
Hi lester, you're doing the right thing, pin 3 should have 5 volts between pin and any ground , for check the potenciometer you should measure the volts between pin 2 and 5 the volts should change between 0 and 5 volst when you push the switch for change the vent flow, you must hear the step motor and if the potenciometer is ok the volts should change between 0 and 5 volts between pin 2 and 5. If the volts do not change the potenciometer is bad or the cable is cut and the IC3914 can´t light on the led, this variation of volts between pin 2 and 5 are for reference of the IC for light on the led. For do that the switch should be plug in the car Well I hope this help, and again sorry for my bad english Regards Eulogio
