Pelican Parts Forums

Pelican Parts Forums (http://forums.pelicanparts.com/)
-   Porsche 928 Technical Forum (http://forums.pelicanparts.com/porsche-928-technical-forum/)
-   -   Headlights go up but don't illuminate (http://forums.pelicanparts.com/porsche-928-technical-forum/533291-headlights-go-up-but-dont-illuminate.html)

cwiert 03-26-2010 08:07 AM

Headlights go up but don't illuminate
 
I've searched this and it seems the likely culprit is the headlight relay. is there anyway to test and confirm this before i go buy a new one?

I read a thread on here where someone took out the headlight relay, opened it up cleaned it out and it got it to work fine. i guess i can try that first.

I also have the '88 944... i doubt it, but are any of the relays in there compatible with the '88 928...just to test if it really is a faulty relay?

MPDano 03-26-2010 08:29 AM

Looks like XXIII-XXIV is the Combination Headlamp Relay

I don't see any other relay in your CE Panel that is the same. At $117, that is an expensive relay. Maybe try 928 Intl for a good used one. I would open it up just to see if you see any obvious issues (burns, broken caps, etc).

MPDano 03-26-2010 08:31 AM

http://forums.pelicanparts.com/uploa...1269621080.jpg

JhwShark 03-26-2010 08:34 AM

A couple of things you can do for testing the big relay.
Feel the top of relay while turning the lights on (long arms or a helper), does it click?

Pull the relay out of the socket, locate Pin sockets for PIN 15 and/or 30 (15 is hot with ig switch on RUN, 30 is always hot), does it have 12 volts (use a trouble light or v meter, pos in the socket and neg to ground)? If you are not getting 12 v to the relay socket it wont get to the lights.

With the relay out of socket connect pin 85 to ground and touch 12v to pin 86; does the relay click? If so the relay is functional. You should also have continuity between 87 (the path to the device)and 30/15.

Relay and fuse chart http://http://928intl.com/repair/Relay/earlyrelay2.htm No other relay to swap within the 928 but it may be similar to other P cars of similar years.
Jon

cwiert 03-26-2010 08:45 AM

Quote:

Originally Posted by JhwShark (Post 5259157)
A couple of things you can do for testing the big relay.
Feel the top of relay while turning the lights on (long arms or a helper), does it click?

Pull the relay out of the socket, locate Pin sockets for PIN 15 and/or 30 (15 is hot with ig switch on RUN, 30 is always hot), does it have 12 volts (use a trouble light or v meter, pos in the socket and neg to ground)? If you are not getting 12 v to the relay socket it wont get to the lights.

With the relay out of socket connect pin 85 to ground and touch 12v to pin 86; does the relay click? If so the relay is functional. You should also have continuity between 87 (the path to the device)and 30/15.

Relay and fuse chart http://http://928intl.com/repair/Relay/earlyrelay2.htm No other relay to swap within the 928 but it may be similar to other P cars of similar years.
Jon

Thank you. Good tips. I'll try them tonight.

Mrmerlin 03-26-2010 04:26 PM

usually this is a bad relay for the headlamps .
Remove the cover and clean all of the contacts and this will buy you time till you can find a replacement

cwiert 03-26-2010 04:28 PM

OK.. i ran those tests and the relay did click and it was getting power...12 volts.
i pulled it took it apart and cleaned it. i plugged it back in and still no light... until i wiggled it. i wiggled the relay and the lights illuminated. i shut the lights off, turned them back on again, and no light. wiggled it again and then light again.

So this tells me that the relay is fine, but it's just not making a good connection, right? i cleaned all the prongs on the relay. I guess now i should try to clean all the plugs where the prongs plug into. maybe us a thin small screwdriver or folded up sandpaper?

dr bob 03-26-2010 04:46 PM

The connectors in the panel insert from the back side, and are retained by little tabls on the connector that pop out. It's possible to use a thin probe to push that little tabe back, allowing the connector to come out the rear. Hint- push the tab back, THEN withdraw the connector. Once removed, you can clean it and tighten it a smidge with pliers.

The poor-man's roadside solution has you twist the tabs on the relay itself ever-so-slightly, so they go into the CE panle connector just a hair crooked. That adds pressure on one side that will get you home. But the currect passing through just part ofthe pin will lead to heat and future failure. Since you have it in the garage and not stuck out on the highway at night, do it right, like you really mean it.

Mrmerlin 03-26-2010 04:55 PM

if the relay will come on with a wiggle inspect the female connectors it plugs into if they look good then the relay probably has a loose connection try soldering the the male pins either inside or out the relay box this might cure the issue

cwiert 03-26-2010 07:20 PM

Quote:

Originally Posted by dr bob (Post 5259991)
The connectors in the panel insert from the back side, and are retained by little tabls on the connector that pop out. It's possible to use a thin probe to push that little tabe back, allowing the connector to come out the rear. Hint- push the tab back, THEN withdraw the connector. Once removed, you can clean it and tighten it a smidge with pliers.

So in order to do this, i'd need to remove the entire panel with all the fuses and relays and those 20-something wiring harnesses on the bottom, right? wow. that seems a little intimidating. I imagine i'd have to label and remove all those wiring harnesses that line the bottom in order to remove the panel, to get to the back of it, right? can i leave all the other relays and fuses in place? the battery will be disconnected, so that should be OK, right?

MPDano 03-27-2010 05:05 AM

Quote:

Originally Posted by cwiert (Post 5260234)
So in order to do this, i'd need to remove the entire panel with all the fuses and relays and those 20-something wiring harnesses on the bottom, right? wow. that seems a little intimidating. I imagine i'd have to label and remove all those wiring harnesses that line the bottom in order to remove the panel, to get to the back of it, right? can i leave all the other relays and fuses in place? the battery will be disconnected, so that should be OK, right?

Looks intimidating but really isn't. Unplug one at a time, mark them, I did a,b,c,d.... from left to right. Counting even the empty plugs as a letter so I didn't plug them in wrong. You'll need to take off the 2 bolts holding a bunch of grounds above the CE (at least on my early OB I had to). You can then pull the panel out. From there, it's just a lot of cleaning. I printed out the diagram which shows what fuses go where and removed and cleaned all the fuse tabs with a wire brush. I then used an electrical cleaner spray and used compressed air to make sure it was dry and any bristles were blown out.

MPDano 03-27-2010 05:07 AM

http://forums.pelicanparts.com/uploa...1269695209.jpg

http://forums.pelicanparts.com/uploa...1269695219.jpg

http://forums.pelicanparts.com/uploa...1269695231.jpg

cwiert 03-27-2010 05:34 AM

Quote:

Originally Posted by MPDano (Post 5260581)
Looks intimidating but really isn't. Unplug one at a time, mark them, I did a,b,c,d.... from left to right. Counting even the empty plugs as a letter so I didn't plug them in wrong. You'll need to take off the 2 bolts holding a bunch of grounds above the CE (at least on my early OB I had to). You can then pull the panel out. From there, it's just a lot of cleaning. I printed out the diagram which shows what fuses go where and removed and cleaned all the fuse tabs with a wire brush. I then used an electrical cleaner spray and used compressed air to make sure it was dry and any bristles were blown out.

OK... I'm inspired now. Thanks. :)
The electrics, overall, seem to be a problem area in this car... so i think i can do a lot of good by removing that panel and cleaning it as much as i can.

dr bob 03-27-2010 07:05 AM

There's a latch release for the lower connectors per the WSM. I haven't needed to pull any yet so can't share guidance on location of that latch. The connectors are keyed, but still a good idea to label them as they come out.

MPDano 03-27-2010 07:12 AM

Quote:

Originally Posted by dr bob (Post 5260743)
There's a latch release for the lower connectors per the WSM. I haven't needed to pull any yet so can't share guidance on location of that latch. The connectors are keyed, but still a good idea to label them as they come out.

Hi Dr Bob,

Yeah, mine weren't keyed to where you couldn't plug the one next to it in the wrong slot. They were keyed to where you couldn't plug it upside down. Labeling is a must and not a smart move if you don't. It may have changed in the later year 928's but I would still label them regardless (like you said).

I also went through all the grey wires on the back of the CE to make sure none were melted and grounded. Check those Relay plugs (receiving ends) as they can get pushed in. Lots of wire brushing on those too. Just make sure to blow them all out since any bristle from the wire brush can create a short.

lfausty 03-27-2010 08:29 AM

MP truely such a inspiration i want to do mine all over again, not! lol

cwiert 03-27-2010 06:47 PM

I guess I'm a little confused. I removed the entire panel. Took out all the relays. Cleaned all the relay posts (male end). Checked all the fuses. But I don't know how to clean all the relay plugs... the receiving ends. Did you literally pull out each wire from the back? Or did you just get a super tiny wire brush and stick it in the hole? I sprayed the entire thing with electronic cleaner, but I don't know how else to get in each plug to clean it out.

MPDano 03-27-2010 07:07 PM

Quote:

Originally Posted by cwiert (Post 5261780)
I guess I'm a little confused. I removed the entire panel. Took out all the relays. Cleaned all the relay posts (male end). Checked all the fuses. But I don't know how to clean all the relay plugs... the receiving ends. Did you literally pull out each wire from the back? Or did you just get a super tiny wire brush and stick it in the hole? I sprayed the entire thing with electronic cleaner, but I don't know how else to get in each plug to clean it out.

I never removed the receiving ends of the Relays. I just used a small bristle brush and cleaned them in place. You just want to make sure they are not pushed in by the Relay Blades. If one is, then push it back up from the back. It "should" lock back in place.

Spray electronic cleaner in the receiving plugs and blow it out with a compressor to make sure no bristles are there and it is all dry before putting it back in service.

I did "not" spray the Relays themselves and I didn't want any liquid to get in the relay body. Just brush the spades and wipe it off.

morriss 03-29-2010 06:44 PM

Quote:

Originally Posted by cwiert (Post 5261780)
I guess I'm a little confused. I removed the entire panel. Took out all the relays. Cleaned all the relay posts (male end). Checked all the fuses. But I don't know how to clean all the relay plugs... the receiving ends. Did you literally pull out each wire from the back? Or did you just get a super tiny wire brush and stick it in the hole? I sprayed the entire thing with electronic cleaner, but I don't know how else to get in each plug to clean it out.

I pulled each one of mine out of the back, one at a time. Took the Drimmel with a brush on the end to each and every one of them and then plugged back in. Then Dremmeled the connectors that hold the fuses in place on the front side of the panel. I figured that if I had the panel out, I might as well do it right so I would not have to pull it again anytime soon. Just my 2 cents.


All times are GMT -8. The time now is 07:58 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2025 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website


DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.