Replaced Headlight relay
01-03-2016, 03:12 PM
#16
Instructor
Thread Starter
I would follow Alan's testing suggestions.
FWIW my 88 S4 did this also , lights come up but wont turn on.
I took the original relay cover off and cleaned the contacts ,
put in some deoxit then it started working as it should.
Is the relay you got the same part number, there are different versions
FWIW my 88 S4 did this also , lights come up but wont turn on.
I took the original relay cover off and cleaned the contacts ,
put in some deoxit then it started working as it should.
Is the relay you got the same part number, there are different versions
Digging through some boxes for my multimeter (moved to SoCal 2.5 years ago and haven't had to use it).
The part number on the old relay is is not legible, I just trusted Sunset on the part number.
01-03-2016, 03:18 PM
#17
Team Owner
The HL relay has 4 contacts inside of it
Please post pictures of the relays you got and or the part numbers
Please post pictures of the relays you got and or the part numbers
01-03-2016, 03:22 PM
#18
Instructor
Thread Starter
I would follow Alan's testing suggestions.
FWIW my 88 S4 did this also , lights come up but wont turn on.
I took the original relay cover off and cleaned the contacts ,
put in some deoxit then it started working as it should.
Is the relay you got the same part number, there are different versions
FWIW my 88 S4 did this also , lights come up but wont turn on.
I took the original relay cover off and cleaned the contacts ,
put in some deoxit then it started working as it should.
Is the relay you got the same part number, there are different versions
Google the part number and found "Headlight Relay, 928 (1987-On)"
Last edited by pluckedchicken; 01-03-2016 at 04:25 PM.
01-03-2016, 06:25 PM
#19
Electron Wrangler
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If the pod motor always drives the pods up & down correctly then that suggests that the headlight switch is in fact OK. The connection that raises the pods also turns them on (but only when they are fully-up - as detected by the motor feedback switch).
When they fail to turn on - it is possible they are misadjusted slightly so the headlamp motor still doesn't think they are fully up yet. This will mean is is still on and driving stalled against the up end-stop (this can only happen with S4 and later reversing headlamp motors). This will cause the HL motor to quite quickly get very hot - it is not rated for continuous or stalled operation.
In this case the cause is an adjustment problem (right on the edge if it only happens some of the time).
Based on your symptoms - I suspect this cause most now.
A means to try this out is to remove the HL motor fuse and to turn the headlamps on (with ignition). Crank up the headlamps manually and see at what point they turn on...? is it the very last moment before they get fully to the top of travel? Is it obvious the adjustment is right on the edge of switching?
Alternatively when this fails see if the motor is getting hot? or install a fused current detector in the fuse slot and see if the motor is continuing to draw power in the up position?
Something like this: 30A ATC fuse current tester
If so adjust the up position limits on both HL pods a bit until it helps make this more reliable (you have to get into the wheel wells to do this) - then re-aim the headlamps.
Alan
When they fail to turn on - it is possible they are misadjusted slightly so the headlamp motor still doesn't think they are fully up yet. This will mean is is still on and driving stalled against the up end-stop (this can only happen with S4 and later reversing headlamp motors). This will cause the HL motor to quite quickly get very hot - it is not rated for continuous or stalled operation.
In this case the cause is an adjustment problem (right on the edge if it only happens some of the time).
Based on your symptoms - I suspect this cause most now.
A means to try this out is to remove the HL motor fuse and to turn the headlamps on (with ignition). Crank up the headlamps manually and see at what point they turn on...? is it the very last moment before they get fully to the top of travel? Is it obvious the adjustment is right on the edge of switching?
Alternatively when this fails see if the motor is getting hot? or install a fused current detector in the fuse slot and see if the motor is continuing to draw power in the up position?
Something like this: 30A ATC fuse current tester
If so adjust the up position limits on both HL pods a bit until it helps make this more reliable (you have to get into the wheel wells to do this) - then re-aim the headlamps.
Alan
01-03-2016, 07:45 PM
#20
Instructor
Thread Starter
If the pod motor always drives the pods up & down correctly then that suggests that the headlight switch is in fact OK. The connection that raises the pods also turns them on (but only when they are fully-up - as detected by the motor feedback switch).
When they fail to turn on - it is possible they are misadjusted slightly so the headlamp motor still doesn't think they are fully up yet. This will mean is is still on and driving stalled against the up end-stop (this can only happen with S4 and later reversing headlamp motors). This will cause the HL motor to quite quickly get very hot - it is not rated for continuous or stalled operation.
In this case the cause is an adjustment problem (right on the edge if it only happens some of the time).
Based on your symptoms - I suspect this cause most now.
A means to try this out is to remove the HL motor fuse and to turn the headlamps on (with ignition). Crank up the headlamps manually and see at what point they turn on...? is it the very last moment before they get fully to the top of travel? Is it obvious the adjustment is right on the edge of switching?
Alternatively when this fails see if the motor is getting hot? or install a fused current detector in the fuse slot and see if the motor is continuing to draw power in the up position?
Something like this: 30A ATC fuse current tester
If so adjust the up position limits on both HL pods a bit until it helps make this more reliable (you have to get into the wheel wells to do this) - then re-aim the headlamps.
Alan
When they fail to turn on - it is possible they are misadjusted slightly so the headlamp motor still doesn't think they are fully up yet. This will mean is is still on and driving stalled against the up end-stop (this can only happen with S4 and later reversing headlamp motors). This will cause the HL motor to quite quickly get very hot - it is not rated for continuous or stalled operation.
In this case the cause is an adjustment problem (right on the edge if it only happens some of the time).
Based on your symptoms - I suspect this cause most now.
A means to try this out is to remove the HL motor fuse and to turn the headlamps on (with ignition). Crank up the headlamps manually and see at what point they turn on...? is it the very last moment before they get fully to the top of travel? Is it obvious the adjustment is right on the edge of switching?
Alternatively when this fails see if the motor is getting hot? or install a fused current detector in the fuse slot and see if the motor is continuing to draw power in the up position?
Something like this: 30A ATC fuse current tester
If so adjust the up position limits on both HL pods a bit until it helps make this more reliable (you have to get into the wheel wells to do this) - then re-aim the headlamps.
Alan
01-03-2016, 09:33 PM
#21
Team Owner
Alan thats a very smart idea that you suggested.
OP can you post a picture of the headlight motor with the arm in the up and down position?
Maybe the arm has moved enough to jamb the motor from going up all the way.
OP can you post a picture of the headlight motor with the arm in the up and down position?
Maybe the arm has moved enough to jamb the motor from going up all the way.
01-03-2016, 10:10 PM
#23
Electron Wrangler
Lifetime Rennlist
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Maybe nothing to do with the lights being on - perhaps just the engine/rad heat - right next to the HL motor. Try driving in the daylight (no lights on) then when the car is plenty hot let it sit for a few minutes and try the lights then.
Alan
07-26-2017, 09:14 PM
#24
Instructor
Thread Starter
Occurred to me, never posted a resolution....
I gave up, and took it to Precision Motorwerks.. turns out PO had put in higher wattage bulbs than the wiring could handle. Over time fried the wiring.
I gave up, and took it to Precision Motorwerks.. turns out PO had put in higher wattage bulbs than the wiring could handle. Over time fried the wiring.
10-23-2017, 10:58 AM
#25
Instructor
My 1984s refuses to dim its lights. It had a 928 618 107 02 relay. I removed it and jumpered between 30a and 56a then 56b. The high and low beams on both sides worked. I ordered a new relay. I cleaned the grounds and checked the 4 headlight fuses. I got a new 928 618 107 05 Friday. I replaced the relay. No change. I removed the dimmer switch and replaced it with the switch from my parts car. No change. I sprayed all the connections with deoxit. I sprayed the old relay inside and out with deoxit. I removed the CE panel and made sure there was no rodent damage and all the connectors were in the sockets. With either relay and any of three switches in place the head lights come up when they are turned on, the brights come on but the dimmer has no effect on the high/low beams. The blue high beam indicator stays on whenever the lights are on. I need some guidance on how to test the switches and the relays. I am aware that there has been a problem with the 928 618 107 05 relays in the past. I am guessing that is my problem but I would like to test both relays before getting another one. Any help would be very much appreciated.