Community Forums

jestal · 09-26-2016, 06:45 AM

Has anyone used the driving/fog lights and understand the logic of why and when they will work?

I tried the driving lights to see if they worked since the lens looked cloudy and the bulbs appeared to be dark and burnt out. Sitting in a parking spot the lights do not work with the key on, headlights on, non-high beams,etc. as I have experienced in different cars for logic. The lights do not work and I hate things that do not work so it has become a quest to determine why they don't work (and what else is not working as a result.)

The driving lights are controlled directly from the SCM via a sense wire to the SCM from the switch with no fuses or breakers so no blown fuses to look for.

I was told the parking brake has to be OFF for the driving lights to work (I always had it on while parked and in and out of the bus checking lights. So...with wheel chocks I tried it in gear, neutral and with and without the parking brake on and with and without the engine running No joy.

Cursory checks of the circuit from the switch to the SCM and the SCM to the lights does not show an obvious problem.

Replace the light bulbs, no joy, Jumpered pins at the switch to bypass switch and no joy. Replaced switch anyway......still no lights

Powered circuit with hard wired aux voltage bypassing the switch. Lights do work so at least some of the wiring is good and the bulbs are good.

Entegra CS no real help. It is a Spartan circuit but they cannot offer help on the problem either. They want me to bring it to Spartan.

Anything I'm missing or other ideas?

voltdoc · 09-26-2016, 06:53 AM

If you have a helper try putting the transmission in drive and see if they come on.

Ann n Gene · 09-26-2016, 11:14 AM

Mine will not come on until o take the emergency brake off AND put the transmission in gear.

2016 45 B Topaz Cornerstone
2014 MKT towed

johnnyreno · 09-26-2016, 01:26 PM

Quote:

Originally Posted by Ann n Gene

Mine will not come on until o take the emergency brake off AND put the transmission in gear.

2016 45 B Topaz Cornerstone
2014 MKT towed

I Think that's the case ann. and gene

Matt D · 09-26-2016, 02:08 PM

I agree, brake off transmission in gear. At least that is how ours works.

-Matt

jestal · 09-26-2016, 07:05 PM

Thanks for the feed back! I did try in gear with the parking brake off and did not get the lights so I'm still searching for the problem. Never give up!!

Matt D · 09-26-2016, 07:27 PM

Al, you did try with the engine running, correct?

I once had a difficult problem that was resolved only with the engine running.

-Matt

jestal · 09-26-2016, 10:24 PM

Matt, yes, had the engine running tried in gear with park brake off. The "trouble tree" is pointing towards a bad SCM but somehow I do not think that is the problem. I had the connectors off at the SCM to check wire continuity and look for missing or bent pins or corrosion. Every thing there looked OK. possibly it might be the driver in the SCM for that circuit but since everything else the SCM seems to work fine I can't see buying a new SCM just for the fog lights circuit. if I still run into dead ends I might just add my own circuit and wiring to bypass the factory system and power the lights independent of the SCM. hard to get that worked up over it though. Just hate to fail in the trouble shooting......

Thanks!! AWC

Gary.Jones · 09-27-2016, 06:32 AM

Al

You started this thread by saying the lights appeared clouded and the bulbs appeared to be black raising the possibility that the bulbs are simply burned out. Have you fed the bulbs directly or done a continuity of the filaments to determine if the bulbs are functional...... Maybe I have forgotten that you said you tried that already....

Gary

jestal · 09-27-2016, 09:20 PM

Hi Gary, The lights didn't look too bad, just slightly fogged or some deposit on the inside of the glass. The bulbs looked a bit dark but I have seen dark looking bulbs work fine so...???? I did pull the bulbs out and they do light up fine with an alternate power source. Put new bulbs back in regardless to be sure and because they were "in stock" I've never been able to tell if the lights ever worked while driving since we bought the coach. just never bubbled up to the top of the list. Looking at the lights I figured it was just bulbs....not. Trouble shooting it without wiring diagrams (which I did finally get from Spartan) was a bit tricky as i was just visually following wires and checking the switch based on preconceived notions of the logic of the switch and wiring.

I've been on another quest the past few days so when i get a chance to drive the coach Thursday I'll be able to do more checking of the lights knowing the engine has to be running, parking brake off and transmission in gear. I did run the wiring one more time today and discovered a pigtail or extension added to the Spartan part of the harness which I had not checked before. Some tugging and pulling to get the connectors to part company and I found a bent pin so maybe that was the problem although I swear i checked continuity on that circuit from the SCM to the switch connector and the line (which includes this pigtail) was OK at the time.

much ado about nothing really as the driving or fog lights are not really something absolutely required but i just want to know why they don't work. Since they are powered by the SCM there must be some logic function in there that governs their operation and that was what I was looking for with the post.