Marker Lamp, Turn signal issue

[Ncostello]

I noticed that my driver side front marker lamp (orange one on the fender side) was out. I looked at the bulb and it looked completely silver on the inside such that I could not see the filament. So I just replaced it.



Now, when I turn on my lights... this particular marker lamp is VERY dim compared to the right side lamp. And the left turn signal indicator on the dash cluster is also lit constantly but somewhat dim at the same time. When I click on the left turn signal... both the corner marker lamp and the dash cluster indicator flash brightly as they should. When I stop the turn signal... it goes back to the marker lamp being dim... and the turn indicator lamp being dim at the same time.



Its just when the parking lamps/headlights are on that I have the problem. If I shut the lights out... the problem stops. I pulled the new bulb out and my dash cluster left turn arrow is no longer illuminated. I wasn't sure if this is a short circuit so I didn't want to press the issue by leaving the bulb in.



What the heck? Do I have a bad flasher fuse or ??? I recently re-wrapped all of my engine bay wiring and didn't notice any issues with shorts or bare wires. I went over all of it and carefully inspected it before re-wrapping in new tape.



I have a feeling this could be a miserable search.

 

[cerberusiam]

Bad ground or a shorted wire somewhere. Check the harnes to make sure it has not rubbed a wire bare on the fenders or rad support.

 

[Ncostello]

I just finished removing, re-wrapping and inspecting the entire harness system. From the battery all the way over to the A/C compressor, down to the transmission and across the side of the engine. Just so it would look nice and neat. I also found some missing plastic harness supports for the firewall and basically made it all look better than new.



During this process I completely unwrapped everything, inspected each wire (found one break and fixed it... I believe it was the fuel gauge because now it works fine), polished all grounds and re-built-re-sealed all those wiring connections where dodge fused 2-3 wires together and cloth wrapped them. All this included going all the way from the firewall down to the lights themselves. Maybe its under the dash then.



So I guess what I'm thinking is that I will only unwrap my new work to a point. Cause I'm definately not removing everything again and re-doing especially since I inspected it once already. This saddens me because I did such a good job of making it better than factory and use OEM looking supports and such.



If it aint easy... I guess I'll have to live without this light. I will look under the dash as well. Like I figured... not fun!!

 

[B.G. Smith]

I agree with with ceberusiam, it is a simple bad ground at the light. That bulb grounds through the socket, the assy. could have lost ground or I have seen just the sockek lose continuity into the housing. If you have an analog volt meter, turn the light on and put one probe on the bulb base and probe the surrounding metal, if you get a reading the ground is bad. bg

 

[PBJ2500CTD]

Check the condition of the socket and ground for the front left (drivers) turn signal. I believe the side marker grounds throught the turn signal/parking light.

 

[Ncostello]

Thanks guys. I will check those things and right soon. Especially the socket. I had a feeling from the way this one looked something was amiss. But I ignored it because I didn't realize it served as a marker and a flasher.



Anybody know where this thing ultimately grounds to? I believe the socket is like a rubber stopper that kinda "pops" into the light housing. So there is no ground "at" the light lens housing itself.



I'll apologize now. I have no electrical diagram for this 91. 5. I WILL get one... promise.



Once in a while I say this in my posts: Support on TDR and the members willingness to help with even the smallest problems are the BEST of any automotive type group on the internet or otherwise.

 

[RedRamAndy]

Yep, check that bulb. Been there, done that. EXACTLY the same problem you had. I had this before many times so I fixed this one in minutes. Good luck.

 

[cerberusiam]

Thanks guys. I will check those things and right soon. Especially the socket. I had a feeling from the way this one looked something was amiss. But I ignored it because I didn't realize it served as a marker and a flasher.



Anybody know where this thing ultimately grounds to? I believe the socket is like a rubber stopper that kinda "pops" into the light housing. So there is no ground "at" the light lens housing itself.



I'll apologize now. I have no electrical diagram for this 91. 5. I WILL get one... promise.



Once in a while I say this in my posts: Support on TDR and the members willingness to help with even the smallest problems are the BEST of any automotive type group on the internet or otherwise.

IIRC, all the lighting is grounded at the top of the radiato support right in front of the battery. Remember having to pull that connection apart to move the harness out of the way. Am thinking all the bulb bases tie back into the ground there.



Check for any corrosion or pieces in the bulb base also that could be giving path for the power to flow.

 

[B.G. Smith]

As stated above, all lights on each side ground to the core support (after they are all connected together) so that may point to the problem being at the light assy. it's self rather than the grounding point of all. bg

 

[Ncostello]

I remember there were a couple of small gauge grounds "fused" together along the way in the harness when I re-wrapped it. I recovered all of them with the glue lined heat shrink. They all looked clean and solid at the connections. I also did clean the ground near the battery on the core support last week. Both the ring terminal that comes from the harness as well as the core support point as well. The engine block is grounded to the battery as well as the block grounded to the frame. All points polished, new Deka battery, new cables and ground straps.



With that being said... I'll spray electrical cleaner in the socket again and do a better job of looking it over. The copper terminals look slightly green but not too shabby or cruddy. There are two wires. A green wire which reads 5. 5 Ohms when checked to battery ground. And a black/yellow stripe wire that reads 1. 5 Ohms when checked to battery ground. Ignition off, light switch off. Green I assume is power both steady on and flash signal. Black is ground I assume. Should both get an ohms reading? Shouldn't the power (green) read infinite since the switch is off?



Here is what it does with the bulb in. The light comes on but very dim. And the left turn signal dash indicator is lit constantly but dim as well If I hit the turn signal (with the ignition on) it flashes brightly as it should as does the turn signal indicator lamp on the dash. The turn signal flashing part works normally with the parking lamps off too.



I did notice that the flash blink rate is about half that of the right side. Kinda slow. Now if the ignition is off and I put the parking lamps on it is dim as well. Except if I pull the turn signal lever (but dont engage the lock) down as if to make a left turn... it brightens up. I can make it flash manually with the ignition off. If I pull it down all the way so it holds itself... the lamp stays on constantly bright.



Mind you that the right turn signal is dead no matter what as long as the ignition is off. The turn signals should only flash if the ignition is on. But this left one comes on but dont flash.



Confused? I hope not. Power is back feeding when the parking lamps are on and getting into the turn signal switch. Thats my take. Which leads me to believe its not in the socket. The socket actually looks pretty good once I re-cleaned it. The lamp should be a constant brightness. Its either off, on or flashing on and off. All the same brightness as its not a dual filament bulb, nor a three wire setup.



Bad light switch? Bad turn signal switch? Or the wiring in between them under the dash? My ground must be OK as the turn function produces the normal brightness. I need to check the ohm readings of the other side in all cases.

 

[PBJ2500CTD]

For the best connection you should burnish those green connectors.
Make a continuity check from the left turn signal socket case to a known good ground. The reading should be ~one ohm.

Wait a minute... ???... You say "All the same brightness as its not a dual filament bulb, nor a three wire setup. " If you are checking the turn signal/parking bulb it should be a dual filament 1157 or 2057 bulb, and be three wire. You may have two to the socket bulb contacts and one to the case of the socket for ground. The side marker should be a 194. A measurement of 12 VDC should be read on the power side of the side marker bulb when the lights or turn signal are on. The other contact should be ground (shared with the parking lamp/turn signal unit) and have ~ one ohm to ground. Any more resistance in a circuit will cause a detour of the current to the path of least resistance - or through the other lights. I just measured an 1157 bulb and the highest resistance was 3. 6 ohms in one element and 1. 8 in another. (This includes the meter lead resistance of . 8 ohms) Both elements of the 1157 share the same ground through the case of the bulb to the socket. There should be two contacts in the base of the turn signal/parking lamp socket one feeding the "low" power element for parking lights and the other feeds the turn signal with a "high" power element. Confirm the proper bulb is installed in the left turn signals,both front and rear, and installed to the correct polarity.
If you were working with the side marker and not the turn signal/parking lamp it is most likely the ground circuit.
What happens with the lights on and application of the brakes; then turn signal and brakes; lights off and brakes/turn signal?

 

[Ncostello]

The side marker lamp on the fender is the issue. It also serves as a "side" turn signal... as it flashes when turning. Not to be confused with the parking lamp/turn signal lamp on the grille. All other lights function normally. The exception is this left side front marker.



The grounds are checking fine and are cleaner than the factory provided. I'm fairly convinced its not a ground issue but rather a power supply issue. I think the marker lamp power is shorting somewhere before it gets to the tiny little bulb. I feel the ground is OK because I can get a nice bright flash when the turn signal switch makes this marker lamp flash. Plus I've checked the grounds with the Ohm meter.



I'll do some real serious checking this evening and start pulling the harness apart and doing a major inspection under the dash.

 

[B.G. Smith]

I hope it's cool where you are and you have a comfortable place to work on the problem because I think you are going to do a lot of tedious work and eventually find the problem is in the marker light or the parking light ground. All the bulbs except the headlights ground through the bulb base. The bulb sockets are just crimped in the housings I believe so that is the first suspect area. If you don't have an old analog volt meter, you can use a piece of insulated wire attached to a known ground source and with the lights on just touch the bare end of the wire to the bulb base or socket and see if the light brightens or the problem stops. Sorry for the rant, hope you have already solved the problem. bg

 

[PBJ2500CTD]

It sure is pointing to the ground for the turn signal/parking lamp. Since you do get a full brightness at the side marker when the turn signal is activated this check shows a good side marker circuit... no shorts or opens. Ground circuit is completed through the tail light.
Turn signal slower than normal = higher resistance (lower current thru flasher).
Dim side marker = shares ground with front turn lamp until turn signal is activated.
I bet if you look at the LF parking lamp element when you activate the left turn signal you will see a faint illumination of the element.
Without proper ground (less than ~1 ohm) in the lighting mode the LF current will seek the lowest resistance path to ground - which is from the side marker/parking lamp through the turn signal element and left turn signal indicator in the instrument cluster. The extra path reduces current through the turn signal flasher hence a slower than normal flash rate, or no flash, depending on the added resistance to the circuit. With the ignition off and you activate the light circuit and set the turn signal switch to the left, the current is flowing from the tail light ground, through the tail light element, through the turn signal switch, to the front turn signal element, and at this point without an adequate ground at the front lamp it takes a detour through the parking lamp element through the headlamp switch to the battery positive terminal. If the proper ground was avaiable the current would flow from front lamp ground through the proper lamp element through light switch to positive terminal. A much shorter path.
One more question: Does the side marker lamp and turn signal indicator lamp in the dash alternate illumination when compared to the left front turn signal or do all flash in unison?
I had the same thing happen with a Jeep years ago. The turn signal lamp socket ground was so badly corroded internally I had to splice in a new socket assembly.

 

[Ncostello]

I'm following your comments. I will be checking here after I get home. Thanks for the continued support. One component I need to keep in mind is whether I'm reading parking/turn signal... . or side marker/side turn signal.



The side marker/side turn signal lamp on this truck absolutely cannot ground through the bulb base or socket or whatever term its called. Its plastic, sealed up and has no metal to it. It fits into a plastic reflector housing. Touching anything to it won't contact any metal or touch the ground at the bulb base. It uses a total glass bulb (tiny) that has the filament wires that come out the glass flat base... like a christmas tree bulb. So the ground to this lamp assembly is through the wiring to it specifically. I can remove the bulb/socket form the housing... hold it in my hand... . and it still works normally. The socket is all plastic on the outside.



I apoligize if I'm reading the responses wrong. I hope nobody get frustrated at my points. But I'll get it based on this input from everyone.



Now... the bigger front parking/turn lamp IS a metal socket. It will all be looked at in length tonight.

 

[PBJ2500CTD]

Try BG's excellent idea for quickly isolating the ground issue. Take a piece of insulated wire and connect to the turn signal socket and to a known good ground. Be sure you have a good connection at both ends. If it is the ground causing the problem everything should work as advertised.
If you have an ohmmeter you can check for the resistance from the socket case to a known good ground. Try unplugging the turn signal/parking lamp and read the resistance at the lamp's plug. You should read the resisance of the bulb elements. Remove the bulb and measure from the respective plug connector to each of the two contacts and the socket. I bet you will find your issue in this area.
The side marker is a simple two wire circuit, one power lead controlled by the lighting circuit and one ground wire going to the combination ground point with the front turn/parking lamps. We just had to get everyone looking at the same area for troubleshooting purposes. The side marker itself appears to be all cleaned up and working well evidenced by a full bright condition. Just understandiing what condition would cause the symptoms becomes the challenge.

 

[Ncostello]

Folks... the problem is solved. And I am ashamed. But for once in my life I'm happy to be ashamed because for me to be right would have required much work for even more failure.



The culprit was simple. The 2057 amber bulb in the parking lamp had the turn signal filament rattling around in the bulb. It was shot. And I would have bet alot that I verified it was working prior to all this. But I must not have.



If the turn filament in either front grille parking lamp assembly is burnt out... it causes a dim side marker and green dash illuminator to light up for the respective side. I verified this by putting the right 2057 in the left socket. Problem solved. Then the right side had the same issue with the entire bulb missing. Maybe its a Dodge warning system that your turn bulb is burned out.



I had both the left park/left marker bulbs next to each other while checking voltages, grounds etc and noticed that when my turn signal flashed... the main turn signal didnt. And I was sure it was.



I knew all my grounds were clean, sockets clean etc. I was worried I was in for it. But alas... the bulb. But not the bulb I was thinking. I had two burned out at once and didn't realize it.



Sorry for much of nothing. I was so focused on that marker lamp because it didn't function and was burnt silver I didn't pay much attention to the other. Like I said... I was sure I checked the main turn signal was flashing. It was night, the headlights were on, the park lamps were on and I was too focused on the side flashing light.



I'm going to go clean all light sockets this evening. And verify all bulbs function. Rear too!!



Thanks for the support and help!!!!!

 

[PBJ2500CTD]

That's great! Glad to hear it was an easy fix. Now you won't have to re-do that nice wrap job.
My old electronics instructor always said start with the simplest thing first... another proven case!

 

[B.G. Smith]

That's great! Glad to hear it was an easy fix. Now you won't have to re-do that nice wrap job.

My old electronics instructor always said start with the simplest thing first... another proven case!

I second that. bg

 

[Ncostello]

I think my grandfather once told me that. Many times in fact. Problem is... I swore I saw that thing functioning. Measure twice... cut once. That one I have down pat!!