No low beam headlights, High beam okay

[Allen Heath]

I'm new to this forum and have been unsuccessful searching for previous topics on my problem.  My current new problem is no low bean headlights, but clearance and high beams work.  I pulled out a headlight bulb, jumpered juice straight to the pins, and both filaments work.  I'm getting lost looking in the FRB for anything obvious (no brown wires or connectors indicating a burning problem), or even places to test for proper voltages. The labels on the board that I think has something to do with the headlights seem confusing in that when I move the steering stalk for High or Low beams green LED indicator lights D5 and D2 (D5: LI HI BEAM RELAY OK, D2: R HI BEAM RELAY OKAY) aren't making sense to me.  Both say for the High Beam Relay but when D5 is on D2 is off, and when D5 is off D2 is on ... but they both say High Beam???.  What connector on that board would have the output LOW beam voltage?   Low beams were working as I recently came home in the rain and they came on with the wipers as they always used to.  After I parked at home a few days later I was taking the coach to storage about dusk and noticed no more low beams.  Coach is '07 Patriot Thunder.  I'm trying to attach pictures of the board's LED indicators.

[Scott Shearer]

Allen,

See if this post sheds any light on your headlight issue.
https://beaveramb.org/forum/index.php/topic,11089.msg76330.html#msg76330

The pcb#8 label is wrong (not the only one). It wasn't corrected until model year 2009.

Attached are images of the updated PCB #8 labels and the pin out for PCB #8 headlight connector J1.

-Scott

[Scott Shearer]

Allen,

Looking at our 2006 PT, I just discovered that not only is the label for PCB#8 printed wrong (HI vs LOW BEAM), but it is 180 degrees off. This makes diagnosing very confusing. The corrected label is also 180 degrees off, the letters ‘F8’ need to go to the bottom.

LEDs per schematic
D4: RED – HI BEAM CRKTBRKR OK
D5: GREEN - HI BEAM RELAY OK
D1: RED – LOW BEAM CKTBRKR OK
D2: GREEN – LOW BEAM RELAY OK
D3 YELLOW – LOW BEAM SIGNAL OK
Looking at the images that you posted, it appears that the first image is correct for high beam (D4) on, low beam (D2) off, the second image would be correct for low beam (D2) on, high beam (D4) off.

I would next use a DVOM to take readings at the J1 terminal block on PCB#8. I posted the pin outs for J1.

Then, depending on your results, follow the suggestions in the above-mentioned thread. You could also report back your results.

**
I forgot about this, back wall of the front run box, up high and to the left is a terminal strip (TS1). The left most terminal is low beam output. I think that this would be the easiest to check for low beam power before it goes through the bulkhead.
**
-Scott

[Allen Heath]

Scott, Thanks for the help. I am not ignoring the hints, but  it will be a couple more days before I can get back over to storage to test more in the cool of the mornings.  By 10 am it's hitting over 100 here.  In fact tonight at 9:30 pm it finally got down to 99.  It's hard to poke around when sweat is  dripping every where.  I'll post results by the weekend.

[Allen Heath]

I went to do more testing today.  Low beams still a no go.  Tried the fog lights and they were a no go.  High beams and clearance all fine.  Then I decided to run the wipers.  Low beams came on!  Then I tried various combinations .... ignition start then off, wipers off, wipers on/off, lights on/off, lights on, high / low beam switch, fog lights, smart wheel buttons, and every other combination I could think of and low beams are WORKING as they should.  I don't know what got unstuck in the low beam circuit by turning on the wipers ONCE.  But everything seems normal for the moment.  Gremlins ....

Thanks for the new label to print out for board #8.  That will help minimize diagnostic confusion in the future.

[Scott Shearer]

Allen,

Glad you got the low beams working. It is hard to know exactly what caused them to start working again, and issues like this can definitely be frustrating.

Assuming your coach follows the 2007 Patriot wiring diagrams in Coach Assist, keep the following in mind if the issue happens again.

The fog lights also not working suggest that there was no signal from the Smart Wheel Controller to the fog light or low beam relays. The odd thing is that the image you posted of the LEDs on PCB#8 says otherwise. There should have been power at the TS1 low-beam terminal.

On your coach, the Smart Wheel Controller controls the low-beam headlight relay circuit on PCB#8. Unlike some other Smart Wheel applications, the actual low-beam headlamp current does not pass through the controller; only the relay-coil current does.

As you know, the Smart Wheel Controller turns on the low beams when the windshield wipers are turned on. It is possible that turning on the wipers “jogged” the low-beam relay inside the Smart Wheel Controller, although that still does not fully explain the PCB#8 LED indications.

If the problem returns, try gently tapping the Smart Wheel Controller with something like a screwdriver handle.

I did not think about it at the time, but it would have been interesting to know if your coach has Daytime Running Lights and, if so, whether they were functional. The DRL circuit is parallel to, but independent from, the regular low-beam function.

-Scott

[Allen Heath]

Scott, no DRL on my coach.

I'm glad the full bulb current doesn't go through the smart wheel.  I've seen pictures of a burnt connector down there.  That was one of the first things I looked for.  Remember it had been raining the day I drove home when the low beams last worked    Probably related some how as it was 'last' in the chain of events.