Electrical/Indicator Light Woes HELP!

[Discobob73]

I remember my EGR light, Fuel indicator light, and Alternator light coming on when I turned the key to initial start mode. (You can hear the fuel pump on) However, they refuse to come on at all. I'm now troubleshooting the problem. Already took it to a shop and they say it's"normal". I disagree, why did it do it before and now it doesn't? I'm thinking the low fuel light will never come on now. Anyways, I've traced the red/black wire all thru the gauge indicator lights. I know the EGR light traces back to the EGR/Speedo box and I've checked the wiring there. I'm assuming it's supposed to have current flowing but still no indicator lights.......bah I've cleaned everything and checked the wiring at the ignition switch as well. The only recourse now is to either a) get a new harness $$$ or b) start exposing wire and look for a burndt one somewhere. I'm really getting frustrated and I don't know what to do now. I've referred to the wiring diagrams and I still can't figure this one out. It's already costed me some $$$ and the problem hasn't been fixed. I could use a Dallas/Fort Worth area Porsche electrical guru to help, please let me know if you can help!

Thanks,
Robert
'76 912e (Posting this in the 912 area too)

[Early_S_Man]

Robert,

I think you can add the shop that told you "It's normal!" to your boycott list in the future!!!

The Alternator warning lamp is a critical situation, since the battery won't be charged without pre-excitation current through that bulb! If the unlit alternator warning lamp coincided with dim headlamps and a dying battery shortly thereafter ... you may have a set of worn brushes in your alternator, but a burned-out bulb is a distinct possibility. If you can find the Blue #61 wire at the Voltage regulator on the relay/fuse/regulator panel ... and ground it with the ignition switch on for testing, that would tell you if the power and bulb are good, assuming the bulb lights during the test. Otherwise get a replacement bulb and spare for your glove box!

I strongly suggest getting a multimeter and doing the investigation yourself ... rather than risking money and the car's health at an unknown shop with an apprentice 'learning' on your car! A search on "Blue *61 wire" turns up several threads you may be interested in reading:

http://forums.pelicanparts.com/search.php?action=showresults&searchid=491048&sortby=lastpost&sortorder=descending

[Discobob73]

If you can find the Blue #61 wire at the Voltage regulator on the relay/fuse/regulator panel .....Where's that? Near the alt in the back or in the bonnet witht he main fuse panel?

Well, I'm a noob when it comes to this. I looked at the Alternator light housing. It has a RED/BLACK Wire and e Blue/Green Wire. How do I check if my battery is getting a charge? It has no trouble starting and lights/radio all work fine. I'll trace the blue wire and make sure it's isn't grounded? The engine is from the 914 and I'm not sure where the blue wire is on the alternator on this one. I appreciate the great response though. At least it points me in the right direction.

Thanks,
Robert

[304065]

Bob,

As ever Warren is right on. So you pulled out the oil pressure gauge and you looked at the bulb holder and you found:

a red wire with a black stripe. this is the switched +12v coming from the ignition switch. DO NOT let this wire get frayed, it will short against the body sheetmetal or the brown ground wire for the gauges and you will spend many hours, as I did, making a new wiring harness from original german wire!

and a blue wire. You say blue/green, which means a blue wire with a green stripe. Are you sure it's not solid blue?

check the bulb.

the way to tell if your battery is charging is to start the engine and measure the voltage at the battery terminals with a multimeter. if you don't have one you should get one, doesn't have to be a fancy Fluke Digital, can be a radio shack cheapie for about $20. Anyway, when you measure the voltage it should be in the 13.5-14.0v range. Any lower, your alternator is not putting out juice, any higher, voltage regulator is kaputt.

good luck!

[Discobob73]

Thanks John, any ideas about the EGR light? I'll check the voltage tonight. Could a kaput voltage regular cause the EGR to not come on either? Section 9 of the Factory Manual states "The EGR indicator lamp comes on when the ignition is turned on and goes out when the engine starts. This wiring hookup provides a method of checking the indicator lamp before each start."

[304065]

No, the VR has nothing to do with the EGR.

So if you verify that the connections on the back of the oil pressure gauge are clean (you can clean them with an ink eraser and some denatured alcohol or electrical contact cleaner), the wires are on there tight, and you are still not getting the lights to come on, that would suggest to me that there is a problem with your 14-pin connectors on the electrical console. There are two: one underneath the console where the wiring harness comes in, and then another one at the rear of the console where the engine harness connects. Both should be cleaned well, that might be your problem.

[Discobob73]

John, wow thanks. I'll try that when I get home. It's where the 3 fuses are for the Rear defroster/Heat blower are correct? At the very end is a molex connector, about 2 inches long and an inch wide. The relay for the heater air blower is there as well. Sometimes I have to jiggle it for it to work. This the best advice so far. I'll let you know how it goes. I'm thinking I'll have to unscrew that panel to get to everything.

[Discobob73]

I have finally got it working. Took it back to the shop. Some wires for the EGR light and a wire was grounding somewhere. As of right now, everything is perfect working order. With exception of the rear defrost window, everything is WORKING!!! woohoo. I'll be posting some pics later on. Thanks!