| Do as I say, Not as I do [message #307264] |
Sat, 17 September 2016 01:53  |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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How long does it take to install two driving lights on the front bumper? Some PO already had something installed there so the +12 volt wiring and holes for mounting already exist in the front bumper mounts. Simple job right? Well it took 5 hours and the wiring under the dash is not hooked up yet.
I initially mounted one light and used a couple of alligator clip leads borrowed from a hangar close by. (One light only draws 1.5 amps.) Nothing! No light. Maybe it is reversed polarity. Tried that. Nothing! I tried the other light. NOTHING! That problem turned out to be an open alligator clip lead. Not the ends, but somewhere inside the wire itself.
I got another lead and now I have only 2 of the 5 LEDs working in the light. What is this now? I tried the other yet to be installed light. It is doing the same thing. It looks like a Chinese manufacturing quality problem. Two with same failure. I decided to put a meter across the light. It was 6 VOLTS under .5 amp load. This dies not make sense. I moved the light to direct across the battery and it works fine. This makes no sense. Where am I loosing 6 volts? The meter leads read close to 0 ohms. I had been using the chrome bumper as the ground. I moved the negative lead from the bumper to the frame of the coach. Wow! it now works. The front impact type GMC bumper is NOT grounded. It measures around 12 ohms between the bumper and the frame it is mounted to with eight 3/8" bolts. I went to the rear bumper and it measures even higher.
So I finally ran the negative leads from the lights to a bolt on the steel frame. Now they work with all 10 LEDs on two fixtures illuminated.
I keep telling people to check the grounds, clean them up, and use the proper ground location. Well, I just got burned by not using the master ground for the engine system. I chose something that was expedient and got burned. I'll leave it that way for now and if it gives me a problem I will run ground leads direct to the aluminum plate under the right hood which is connected to the engine master ground.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Do as I say, Not as I do [message #307275 is a reply to message #307264] |
Sat, 17 September 2016 11:32  |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Ignore the obvious, that is how we are trained. Sometimes I over think the
obvious to a fault, too. Golly, I hate it when I remind myself to K.I.S.S.
But, at some time our training and experience kick in. You are not likely
to forget that one for a good long time. Thanks for sharing, it might just
help someone else down the line. The car club that I belong to has the
"busted mallet" trophy that we award to the most bone headed stunt
performed by a club member during the year. I so far have avoided being a
recipient of it. (Grin)
Jim Hupy
Salem, Or
On Sep 16, 2016 11:54 PM, "Ken Burton" wrote:
> How long does it take to install two driving lights on the front bumper?
> Some PO already had something installed there so the +12 volt wiring and
> holes for mounting already exist in the front bumper mounts. Simple job
> right? Well it took 5 hours and the wiring under the dash is not hooked up
> yet.
>
> I initially mounted one light and used a couple of alligator clip leads
> borrowed from a hangar close by. (One light only draws 1.5 amps.) Nothing!
> No light. Maybe it is reversed polarity. Tried that. Nothing! I tried
> the other light. NOTHING! That problem turned out to be an open alligator
> clip lead. Not the ends, but somewhere inside the wire itself.
>
> I got another lead and now I have only 2 of the 5 LEDs working in the
> light. What is this now? I tried the other yet to be installed light. It
> is
> doing the same thing. It looks like a Chinese manufacturing quality
> problem. Two with same failure. I decided to put a meter across the
> light. It
> was 6 VOLTS under .5 amp load. This dies not make sense. I moved the
> light to direct across the battery and it works fine. This makes no sense.
> Where am I loosing 6 volts? The meter leads read close to 0 ohms. I had
> been using the chrome bumper as the ground. I moved the negative lead from
> the bumper to the frame of the coach. Wow! it now works. The front
> impact type GMC bumper is NOT grounded. It measures around 12 ohms between
> the
> bumper and the frame it is mounted to with eight 3/8" bolts. I went to
> the rear bumper and it measures even higher.
>
> So I finally ran the negative leads from the lights to a bolt on the steel
> frame. Now they work with all 10 LEDs on two fixtures illuminated.
>
> I keep telling people to check the grounds, clean them up, and use the
> proper ground location. Well, I just got burned by not using the master
> ground
> for the engine system. I chose something that was expedient and got
> burned. I'll leave it that way for now and if it gives me a problem I will
> run
> ground leads direct to the aluminum plate under the right hood which is
> connected to the engine master ground.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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| Re: Do as I say, Not as I do [message #307306 is a reply to message #307264] |
Sat, 17 September 2016 19:49 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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Since the energy absorbers are paint coated before assembly then charged with oil and nitrogen gas, that's 3 things that sort of don't conduct. I wonder if anyone ever touched bumpers, then used the pos and neg jumoer cable to make a ling positve, then smoked the energy absorbers when they hit the key?
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Do as I say, Not as I do [message #307313 is a reply to message #307306] |
Sun, 18 September 2016 00:40 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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I had a similar situation on my Colorado pick up when I installed a 7 pin trailer harness / connector. The assembly came with a connector to plug into the flat 4 pin connector normally supplied by GM for trailers. Then the assembly supplied 4 additional wires. The three that you would expect and a much heavier ground wire with a big lug on it. Well I hooked the ground to the frame and it did not work. It turns out that GM used the cab body for ground and there is no electrical connection between the cab body and the frame there is also no electrical connection to the truck bed. That one also took me a while to figure out.
I have also done the bumper to bumper thing to jump cars. I'm glad I never tried it on my GMC.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Do as I say, Not as I do [message #307787 is a reply to message #307264] |
Sun, 25 September 2016 14:13 |
jw mills
Messages: 199
Registered: September 2006
Karma: -30
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Senior Member |
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Ken, I guess I've worked on locomotives too long. Their electrical
system "floats" above the chassis, so I'm used to running ground wires.
So I have to rely on other things to get my "Well, DUH" moments.
On Sat, 2016-09-17 at 00:53 -0600, Ken Burton wrote:
> How long does it take to install two driving lights on the front bumper? Some PO already had something installed there so the +12 volt wiring and
> holes for mounting already exist in the front bumper mounts. Simple job right? Well it took 5 hours and the wiring under the dash is not hooked up
> yet.
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