Interior Light Delay Relay help
04-29-2010, 12:52 PM
#16
Drifting
I used my ipod touch to time the delay on my 90' S4.
With the maintainer/charger installed (about 13.4 volts ), the delay is 21 seconds. I would expect a slightly shorter period partially charged 12V battery.
For another test with the relay removed from the car, you can test the (-) door switches for proper function. Do this with your multimeter set to the lowest ohms setting and check for continunity with chassis ground at the relay socket. With a piece of stranded wire gently insert (just to make contact) into the socket where relay pin TK goes in, and measure ohms between chassis ground (nearest metal object). Do this measurement with all three doors closed. You should see open circuit. Repeat the same measurement, but with one door opened. This time you should see zero ohms between relay socket for pin TK and chassis ground. Again repeat the same measurement for the other two doors. This test will verify your door switches are sending the correct signal to the relay.
With the maintainer/charger installed (about 13.4 volts ), the delay is 21 seconds. I would expect a slightly shorter period partially charged 12V battery.
For another test with the relay removed from the car, you can test the (-) door switches for proper function. Do this with your multimeter set to the lowest ohms setting and check for continunity with chassis ground at the relay socket. With a piece of stranded wire gently insert (just to make contact) into the socket where relay pin TK goes in, and measure ohms between chassis ground (nearest metal object). Do this measurement with all three doors closed. You should see open circuit. Repeat the same measurement, but with one door opened. This time you should see zero ohms between relay socket for pin TK and chassis ground. Again repeat the same measurement for the other two doors. This test will verify your door switches are sending the correct signal to the relay.
Last edited by borland; 04-29-2010 at 05:29 PM.
04-29-2010, 12:58 PM
#17
Supercharged
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Thanks. Can't wait to try your test method tonight.
04-29-2010, 07:05 PM
#18
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A $150. seams like a bargain at this point, geez looking at the inside that's no standard relay like Alen said. It's kind of like the Auto Kick down on a ’91 w/all those components. 
I thought there was a VW/Audi relay that would give out an interior light delay?
I thought there was a VW/Audi relay that would give out an interior light delay?
12-02-2015, 01:16 AM
#22
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Ok did the bench test as talked about, I get a click when I hit the TK pin with ground, but just as soon as I let off, it clicks again.... No delay..... I assume that means a bad relay correct?
12-02-2015, 02:48 AM
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also used a jumper from 31 to 31L and the lights work....also did the bench test as talked about above, I get a click when I hit the TK pin with the ground, but just as soon as I let off, it clicks again.... No delay..... I assume that means a bad relay correct?
12-02-2015, 08:08 AM
#24
Racer
I'll give this a shot.
When you hit tk pin to ground do the lights come on, or just hear the click? It seems to me the click is the relay pulling in.
On the bench test I would check continuity (ohms) at 31 and 31L when you hear the click it should close the circuit. If no continuity with a click it's a bad relay.
If that's working the lights should come on, and off, but without the delay off function.
When you hit tk pin to ground do the lights come on, or just hear the click? It seems to me the click is the relay pulling in.
On the bench test I would check continuity (ohms) at 31 and 31L when you hear the click it should close the circuit. If no continuity with a click it's a bad relay.
If that's working the lights should come on, and off, but without the delay off function.
12-02-2015, 12:45 PM
#26
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Hmmm...my interior lights all go on and off just fine with the door switches but there's no delay. They don't come on when I turn ignition off (should they? I may have misunderstood what someone said) they just come on with the door open, and off with it closed. Is this a reasonable partial failure mode for the relay, or should I be looking for something else?
12-02-2015, 12:51 PM
#27
Racer
http://shop.928intl.com/Relay-Interi...28-618-225-01/Looking at the images AO uploaded, it may be possible to pull the cap off the relay, and clean the contact points on the relay mechanism itself.
12-02-2015, 12:59 PM
#29
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12-02-2015, 01:01 PM
#30
Racer
Hmmm...my interior lights all go on and off just fine with the door switches but there's no delay. They don't come on when I turn ignition off (should they? I may have misunderstood what someone said) they just come on with the door open, and off with it closed. Is this a reasonable partial failure mode for the relay, or should I be looking for something else?
Using Alan's post
Pin - Function
==========
31 - Ground (needed)
31L - To interior lights (needed)
T/TK - Negative trigger from door pin switches (needed)
30a - Power for higher relay functions (optional)
15a - Ignition - truncates delay with ignition on (optional)
31Z - Negative Lock - truncates delay when locking (optional)
I think 15a is to truncate the delay OFF. So when you turn the ignition switch, and the doors are closed the lights go off.
With the delay missing, it could be truncated(guessing here) with either 31Z or 15a. One way to test would be to check 15a for power when you close the door. Then check 31Z for ground with the door closed. If either of these are true the problem is elsewhere.
I hope Alan
chimes in to either correct me, or 
I am a novice on these cars, but have worked with industrial controls for 20+ years.