Electrical - Turn Signal, Horn, Parking light

[MMoyle]

Last week while I was driving in a heavy rain storm, the right turn signal starting blinking rapidly. I initially thought it was a bulb, but that was not the case. I also noticed the following behaviors as well:

1. Horn no longer works. When I press the horn, the right turn signal dash light comes on.
2. The passenger side parking light does not work.
3. The hazards work fine.
4. Left turn signal and parking lamp work fine.

From what I have been reading it appears to be a ground issue. Have any of you experienced this issue? If so, what was the solution? I checked a few grounds on the passenger side fender with a multi-meter and they appear to be fine but I am sure there are others I am not aware of to check.

Thanks
Mike

 

[GAmes]

I hope you are aware that the parking light and the turn signal use different filaments in the bulb, so just because one works doesn't mean the other one should. Two separate circuits. If the hazards work the flash filaments are good. The factory service manual will show every ground in the system, along with a diagram where it is located. There is also wiring diagrams to explore.

 

[crabman]

You have a floating ground. Get a wiring diagram and look up the w/w circuit. I bet that the other items that are wacky share the same common ground. Ground may check good with a meter{very little current} but not be good enough for the amount of current that the circuit uses. E=I x R < never wrong! It is best to take apart the grounds, clean surfaces and reinstall, then you know for certain that is NOT the problem.

 

[brucejohnson]

The indications you describe point somewhere around ground point G100 and splice S150. Most likely is G100 which is under the hood, on the left side, just left and aft of the washer bottle location. It is on a horizontal panel (frame?) with a nut securing the ground connectors to a protruding threaded stud.

 

[MMoyle]

Thanks for the reply guys. I had some time today to look at the G100 ground and although everything looked fine, I took it apart, cleaned the ends, etc. That did not solve my problem. If the horn went bad, could that cause this behavior? I did not have enough time today to check out the horn, but I plan on taking it out tomorrow and inspecting it. I will let you know how I make out.

 

[crabman]

You can check the operation of the horn by disconnecting the feed wire at the horn and use a jumper wire from + battery to horn. Can check the grounding by using same jumper wire only connect it to the negative to see if you have a bad ground and try the horn.
For the turn signal check to see if the bulb is good first., then power and grounds. I was taught by very smart man who said, "Electrical things can be very hard to find or very simple. Start at A and go to Z." Hence, is the light bulb good?

 

[Road Dog]

I've even had a dual filament bulb go bad -- one filament sags and touches the other creating a short.

 

[MMoyle]

Here is what I have been able to determine:

1. Both horns work fine when I send 12V to them
2. I confirmed with a multi-meter that the connectors to the horn are getting 12V when I press the horn button on the steering wheel. I connected the multi-meter to the +/- of the connector itself. So that would tell me that ground and power is good to the connectors.
3. I confirmed that the bulb is good by swapping the bulb from the other side that I know works.
4. I confirmed that I am getting 12V for the parking lamp on the passenger side via the bulb connector (using ground at the connector).

What else should I be checking?

 

[DavidC]

You need to load the circuit, a meter or test light does not do that. One strand of wire and usually electronic's may show voltage but will drop quickly under load. We use to solder 3 lamps together in parallel to test some B52 circuits as that would load the circuit.
https://support.alldata.com/sites/main/files/file-attachments/electrical_circuit_testing.pdf

 

[crabman]

^^^
What DavidC just posted!

 

[brucejohnson]

DavidC and crabman have the right troubleshooting thoughts; Road Dog has a good point...experienced that one myself, more than once! If you can, make a ground jumper to jump from the horn negative terminal (leaving the connector connected to the horn) to a good ground point then attempt the horn and light operations. Go to the other horn and repeat the test, then to the turn signal/parking socket ground and repeat test. This would bypass the original ground and confirm the ability to carry a load through the jumper vs. original ground. I'll look at the FSM wiring diagram again and see IF there may be other potential issues lurking. But right now it still appears like a bad ground.

Common/ground paths for the low/high note horns and the right front park/turn signal lamp, are each thru a Z1 18 BK wire, to splice S150, then out from S150 thru wire Z1 20 BK to ground G100. G100 has numerous ground circuits attached. The issue should be somewhere from ground G100 to splice S150.
If a wire has corroded under the insulation, or has sufficient broken conductors (strands), or some other mechanical defect it will not carry the designed load as previously mentioned by crabman and DavidC. A voltmeter or ohmmeter will indicate a potential or continuity, but will not allow sufficient electrons to flow through the compromised conductor(s). If you can place a jumper at a known good ground point and each one of the three loads' ground connector, you would provide a ground path bypassing the suspected defect.
Good luck with your troubleshooting.

 

[DavidC]

I see joint connector 3 is common to horns and right parking light before going to g100.

 

[brucejohnson]

I see joint connector 3 is common to horns and right parking light before going to g100.

Which page is that on David? I got lost on that one. As Bugs Bunny one said...I knew I shoulda taken that left turn to Albuquerque...

 

[DavidC]

Ok, I could find no info/location in the FSM on joint connector 3. I did find it here tho and maybe the perfect location to be effected by weather
#ad

https://www.cumminsforum.com/threads/joint-connector-3.479043/

 

[DavidC]

Bruce 8W41-2 cigar lighter /horn

 

[brucejohnson]

Bruce 8W41-2 cigar lighter /horn

Thanks Dave! Is that JC 1 power source for horns out of horn relay?
I think the link you posted with the mystery connector is for the snow plow (lighting) package. Their 01 wiring diagram references were not even close to what the 02 diagrams show. I can't find anything in my 02 FSM for snow plow or Aux systems.

 

[MMoyle]

Thanks again for all of you that responded. I am grateful for all the support I get from TDR. Tomorrow I am going to look at splice S150 to see if that is the culprit. Given the location of the splice leads me to believe the weather could have damaged it. I will keep you posted.

 

[DavidC]

Thanks Dave! Is that JC 1 power source for horns out of horn relay?
I think the link you posted with the mystery connector is for the snow plow (lighting) package. Their 01 wiring diagram references were not even close to what the 02 diagrams show. I can't find anything in my 02 FSM for snow plow or Aux systems.

Yeah, another joint connector only that one says it's in the PDC. I can't find anything about joint connectors. The horns and the right parking light share the same JC 3. I am surprised the horns even have a ground wire, in my day's the horn was grounded when you bolted it to the body. I guess one way to find out if it's a ground issue would be to run a jumper from the horn ground to the batt. negative and see if they work, if it hasn't already been done.

 

[DavidC]

I finally found something on JC 3 under ground locations
Joint Connector
No. 3
Near
Powertrain
Control Module
N/S
No location diagram.

 

[brucejohnson]

Thanks again for all of you that responded. I am grateful for all the support I get from TDR. Tomorrow I am going to look at splice S150 to see if that is the culprit. Given the location of the splice leads me to believe the weather could have damaged it. I will keep you posted.

View attachment 123474

Before digging into the wiring harness too deeply try the ground jumper troubleshooting task first. No sense ripping apart something that could be perfectly good and potentially inject more problems.