having a little problem with the gen light on my 1970 cutlass. It just came on. I have converted over to a newer style alternator, and it wasn't on before its putting out around 14 volts checked at the battery. I don't know if it's anything that needs to be worried about. Might just pull the bulb out of gauge. Any thoughts? And be nice. lol.

 

Which alternator did you go with? Did you install an internal reg vs an external and make the proper wiring adjustments?

 

Yes it is an internally wired alternator with the wiring harness for it . I bought the harness for that style alternator is there something I need to be looking for?

 

What is the brand name (manufacturer) and model number of the ALT? You do not want to remove the bulb from the gauge, you want to correct the issue causing the bulb to illuminate.

 

Someone please feel free to correct me, but from what I recall:GEN light ON means there is a Voltage differential across the bulb. Start by tracing the Pink and Brown wires
.

 

Yes it was originally external regulated but I have updated to an internally regulated and bought the harnesss for this regulator

 

OK Thanks for the clarification. It helps if you isolate the GEN Light On to a specific Ignition Key position. Try ALL of these positions and jot down when is it ON and when is it OFF. This will help which circuit maybe suspect
.

 

What are the chances my board has gone bad? I have no other lights that work including the back lights. The gas gauge does work.

 

What 'board' are you referring to? You have no other lights? No headlamps, no tail lights, no dome light, etc.? What are 'back lights'?

 

I have no other lights on that gauge.

 

Did you check the 4A INST LPS fuse?

 

Yes. I have lights on the speedometer and the aftermarket gauges that I wired in that work with the dimmer on the headlight switch.

 

You replaced the original (external VR) ALT w/ a newer/different (internal VR) ALT. You used an adapter wiring kit (harness) supplied w/ the newer/different (internal VR) ALT. This wiring kit was supplied w/ the newer/different (internal VR) ALT? Was there a period of time when the ALT lamp did NOT illuminate while the engine was running? You stated the ALT lamp "...just came on..." That, in itself, doesn't say much. Was there a period of time when the ALT lamp did NOT illuminate w/ the engine running w/ this newer/different ALT?

 

You have not told us what ALT you installed in this car. Likely if you installed a 12SI ALT & the wiring to convert to a 12SI ALT was not done correctly, the GEN light will stay on. That's why both me & Eric asked what ALT you installed in Post #2 & Post #4.

 

The alternator came from auto zone remanufactured. Yes there was a period of time when the light was not coming on. I replaced the alternator after the light was staying on. The charge rate at the battery was low so I replaced it. But the light was still on. Going through it and checking wiring again tomorrow

 

Tough to follow the course of events as described; or as I was following along.

There was a period of time when the light was not coming on w/ engine running with the older (original?) style (external VR) ALT installed I believe is what you're saying. Then, one day with the engine running the (external VR) ALT light came on. At this point perhaps (supposedly) you measured the voltage at the battery with the engine running at idle and the charge rate was low so you elected to replace the (external VR) ALT w/ the (internal VR) ALT. So, the ALT light first began to remain on while using the old (external VR) ALT. I guess you considered the original style (external VR) ALT was the issue that's why you elected to replace it, but you replaced the original (external VR) ALT w/ an internal VR ALT as you suspected the low charge rate demonstrated the ALT must be bad & this was causing the ALT light to remain on. Yet, prior to the ALT replacement the ALT light began to remain on even before the ALT replacement.

Without digging perhaps unnecessarily into any prior diagnostics/troubleshooting of the ALT or the VR you simply replaced the ALT as you suspected the ALT was bad because it demonstrated a low charge rate - this is where you are today, correct? A re-manufactured (internal VR) ALT installed in replacement of an original style (external VR) ALT w/ an illuminating ALT light & a new (internal VR) which measures 14VDC engine running @ idle. So, the original issue (ALT light remained on) occurred even before the new ALT was installed.

You need to specifically state the model number and manufacturer of the internal VR ALT and/or the style of the internal VR ALT you installed (likely either a 10SI, 12SI or CS130 alternator). The fact you purchased it @ Autozone is no help (at all). You have a receipt you can provide the manufacturer and/or model number? At the very minimum take a picture of the side and the back of the new (internal VR) ALT and post it here. There are specific types of wiring kits (harness adapters) which are germane to the type (10SI, 12SI & CS130) ALT you installed. Did Autozone provide an adapter wiring kit? Did you purchase separately a wiring adapter kit? Make your own?

 

Does the ALT light stay on with the key inserted into the IGN SW but NOT in the START position?

 

Pulled the gauge out and had some loose pins in the circuit board. Resoldered them and problem gone. Thanks for all of the help and input.

 

Chuck - This is absolutely amazing. In a gazillion years I would never have suspected.

I do own a 2003 Ford F-250 and many of the Ford trucks have issues with gauges which require simple reflow of solder >>> Circuit Board Medics. I removed my instrument panel, sent it in & had it back in a week.

Glad you found this issue - way to go.

 

I also suspect my bulbs. I have switched over to led which are polarity specific. I went through with an external power source and made sure they were I the correct way. After reading some of your comments and looking through my manual I realized they all share the same pin for power and the signal pin is actually a ground. Works great now. Comes on when the ignition is on and goes out when started. 1 more thing off the list.

 

I'll say you're doing a spanking nice job of refurbishing some electrical gremlins. IIRC, you also performed an R&R of the wiring harness? Well done, sir. And, yeah, LEDs are polarity specific.

 

Garage days. Some of them can be frustrating

 

I've never done a wiring harness R&R. For years I've maintained a stock (work bench) supply of reels of color coded wiring. I likely have replaced most wiring contained in wiring harnesses one wire at a time.
But, they're color coded to match a wiring diagram and of the correct AWG. Keep up the fine work.

 

Noting similarities in shelving used in your garage and areas of my man-cave.