Rear spoiler controller problems (continued)
05-25-2007, 07:58 PM
#1
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Rear spoiler controller problems (continued)
This follows on from my earlier thread about my inoperative spoiler, but the symptoms have changed somewhat and I'm closer to finding the solution, although I still need help.
The latest symptoms are the spoiler now rises at speed or by operating the console switch, but the only way I can lower it is by powering up the motor by connecting pins on the controller plug, thereby bypassing the controller. I noticed today that turning the console switch either left or right does actually activate the UP or DOWN relays inside the controller, but only activating the UP relay makes the spoiler move. The DOWN relay activates but the spoiler doesn't move, suggesting a fault inside the control module.
To investigate this further I bench tested the controller as follows. I connected 12V+ to pins 6 and 7, and ground to pin 5. Then I bridged pins 9 and 11 to simulate the manual switch being turned to RAISE. This produced a voltage of +11.75V across pins 3 and 4 (ie.output to the motor). Next I bridged pins 10 amd 11 to simulate the manual switch being turned to LOWER. This time the voltage across pins 3 and 4 was just -0.07V, which explains why the spoiler doesn't lower.
What could cause this? The fault obviously must lie somewhere in the controller. Could it be dirty contacts on the DOWN relay, or a bad connection on the circuit board, or a failed component?
I had the controller looked at earier today by an electronics specialist. He replaced a couple of slightly leaky condensers but couldn't find any failed components. There are two ICs in there which he couldn't check other than by replacing them, but could they be causing the problem?
Any ideas?
The latest symptoms are the spoiler now rises at speed or by operating the console switch, but the only way I can lower it is by powering up the motor by connecting pins on the controller plug, thereby bypassing the controller. I noticed today that turning the console switch either left or right does actually activate the UP or DOWN relays inside the controller, but only activating the UP relay makes the spoiler move. The DOWN relay activates but the spoiler doesn't move, suggesting a fault inside the control module.
To investigate this further I bench tested the controller as follows. I connected 12V+ to pins 6 and 7, and ground to pin 5. Then I bridged pins 9 and 11 to simulate the manual switch being turned to RAISE. This produced a voltage of +11.75V across pins 3 and 4 (ie.output to the motor). Next I bridged pins 10 amd 11 to simulate the manual switch being turned to LOWER. This time the voltage across pins 3 and 4 was just -0.07V, which explains why the spoiler doesn't lower.
What could cause this? The fault obviously must lie somewhere in the controller. Could it be dirty contacts on the DOWN relay, or a bad connection on the circuit board, or a failed component?
I had the controller looked at earier today by an electronics specialist. He replaced a couple of slightly leaky condensers but couldn't find any failed components. There are two ICs in there which he couldn't check other than by replacing them, but could they be causing the problem?
Any ideas?
05-25-2007, 09:20 PM
#2
Rennlist Member
It sounds like the transistor went south. I believe it's a BC 337 which there are a lot of suitable replacements. Check out this post:
Spoiler controller
Get your electronics expert to change that bugger out!
Spoiler controller
Get your electronics expert to change that bugger out!
05-26-2007, 06:30 AM
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Hi Mojorizing
I'll ask my electronics man to look at the transistors again when he re-opens after the Bank Holiday, but that was the first thing he checked and he decided they were ok.
I've been studying Springer's thread for about a week and have been emailing him. My knowledge of electronics is almost zero as you can probably tell, but the fact that the DOWN relay does activate when it receives the input from the switch but only sends a very small voltage to the motor (compared to the full 12V when the UP relay activates), suggests that the fault may be a bad contact rather than a failed component. Does that sound logical?
Mike
I'll ask my electronics man to look at the transistors again when he re-opens after the Bank Holiday, but that was the first thing he checked and he decided they were ok.
I've been studying Springer's thread for about a week and have been emailing him. My knowledge of electronics is almost zero as you can probably tell, but the fact that the DOWN relay does activate when it receives the input from the switch but only sends a very small voltage to the motor (compared to the full 12V when the UP relay activates), suggests that the fault may be a bad contact rather than a failed component. Does that sound logical?
Mike
05-26-2007, 08:16 AM
#4
Rennlist Member
Hi Mike,
Yes, if the down relay is pulling in, then it could be dirty contacts or a broken solder trace, it's not the transistor. Trace out the path the power thru the relay contacts and perform the bench test with the cover off, probing with your VOM. Actuate the relay and measure the ohms across the contacts. Sounds like you'll be driving with a fully operational spoiler soon.
Kevin
Yes, if the down relay is pulling in, then it could be dirty contacts or a broken solder trace, it's not the transistor. Trace out the path the power thru the relay contacts and perform the bench test with the cover off, probing with your VOM. Actuate the relay and measure the ohms across the contacts. Sounds like you'll be driving with a fully operational spoiler soon.
Kevin
