mb911

ok tested it again today this is what I have again to clarify.

up manual switch works, Resistance test at the micro switch plugs comes back good, Down manual switch does Not work,

Driving the car the spoiler goes up on cue but does not retract.

If I open the module up I can manual push on the relay contacts and it will go down with the key on of course. Up again is no issue.

so does this point to the module? I would assume a bad relay or diode for that circuit what else could it really be?

mojorizing

Sounds like it could be either the coil on the relay is open, or the transistor that drives the relay is faulty.

https://rennlist.com/forums/964-foru...ighlight=bc337

mb911

does each relay have a separate transistor? the reason I ask is the up relay functions as it should

mojorizing

Yes, each relay has it's own transistor.

mb911

ok thanks pm'd springer though notheard back hopefully soon. I really want to get this thing to work properly. Thanks for all the help thus far

mojorizing

If you're up to it, we could at least identify what component has failed. Let me get a pictorial of the test points, and you can test the various points as you operate the switch. This requires that the module case be removed and a VOM with micro clips or a second person to operate the switch.

mb911

sounds good let me know

mb911

Well not heard back from Springer so not sure if he does this service any more. any other thoughts?

mojorizing

I should have time today to put together a troubleshooting guide.

spentmiles

I just subscribed to this thread, I have spoiler issues going on as well. for about the last 6 months at random it would not go up at the requisite speed, and then at about 60mph it would send up the ! alarm, again still not extending. As I mentioned this was random, maybe once every 10-15 drives and very sporadic.

Today It did it on a little evening drive with the family for some dinner and upon returning home I spent a few minutes troubleshooting, motor works fine with no binding etc (hooked up external 12v) works up and down. raised it up manually (direct 12v) and then hooked motor back into wiring harness and switch would not lower it. made sure micro switches had engaged.

Have not pulled the passenger seat to look at the control module or relay (1990 C4)

my gut tells me the control module is the bad component, since it neither rises/lowers at speed or with the switch, and possibly the rely as well since it does not rise at 70mph or whatever the high limit is

(above the ~43mph normal rise operation).

Hope to pull the seat this weekend, will be interested in any trobuble shooting guide mojorizing can put together and if there is someone willing to test/repair the module that would be fantastic

mb911 keep us posted on your situation regarding the spoiler and I will do the same

mojorizing

I'm not to sure about troubleshooting the module while it's connected and under the dash...I found it cumbersome if not impossible....

Two red circles mark points for voltage tests

One is for the down coil - should read 12vdc (with respect to a good ground) normally, when the switch is thrown it should go near 0 volts and the relay should pull in. If you get the drop without the pull in, the coil is bad.

The other is the base of the down transistor - it's tough to get a probe on the middle lead, but you should see and increase in voltage when the manual switch is activated down.

If you take reading from the bottom of the pcb, you need to realize that the circuit is coated with a clear film - you need to work the probe thru this film into the solder to get a reading.

I'm thinking it may be best to remove the module and measure the various resistances to find the trouble due to the likelihood of shorting something out as you try to get at the circuit.

spentmiles

Thanks Mojorizing. pulled the seat and the spoiler control. same as your pic. what should I test if I cannot get the spoiler to go up, either manually or at speed. I am assuming another 3 prong transistor and the other relay? I am getting a click on the control module when activating the console switch.

I found a few other threads I will read this weekend on testing spoiler control. It would be great if Springer responds he is not to far from me in Atlanta

again any advice is helpful. before I take the plunge on a new/refurb spoiler control

mb911

I bought a spare with a bad diode so I plan on fixing both once I figure all this out. the parts seem cheap just need to understand it fully who knows maybe I will offer exchanges once I have them figured out LOL! thanks for all the help thus far. will update shortly

mojorizing

Spentmiles,
Check fuses #37 - 15amp and #17 - 7.5amp in frunk.

spentmiles

Thanks Mojorizing. Had some time to troubleshoot today.

Fuses Good, also checked power at the spolier control module and that was good.
Checked microswitches continuity good.

noticed the down relay was "welded" shut. cleaned it best I could and freed it to move, got the spolier to work 3 times in the garage with the switch and then it started acting up again, from my testing it appears the down spolier keeps engaging, which prevents the spolier form going up with either the switch or at speed. Was able to slip some paper between the down relay, and verified that the up relay and switch work as expected.

At this point, I could try and replace the relay, it does have a PN, and while I am at it replace the up and down resistor while the soldering iron is out as a "while you are in there", Or source a new/used/refurb spoiler control module.