Last post on Jan 14, 2012 at 10:02 PM
You are in the Chevrolet Suburban & Tahoe
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Chevrolet Tahoe, Chevrolet Suburban, Chevrolet Tahoe Limited/Z71, Towing, SUV
#37 of 63 2004 Tahoe Trailer Wiring Problems
Sep 05, 2009 (9:25 am)
I have a 2004 Chevy Tahoe, which apparently has a wiring harness problem.
I have two trailers, both with new wiring harnesses and light assemblies.
ALL Tahoe lights work fine without a trailer connected.
Trailers have good grounds.
The Tahoe plug at the back tests “good” on all connections UNTIL the trailer is plugged in. Then the lights go crazy.
The Tahoe ground then tests “hot”
Tahoe lights: none on trailer
Brakes lights: none on trailer
Left Directional: good on trailer and Tahoe
Right Directional: none on trailer; Tahoe works, but both tail lights come on
Brake & left directional: Trailer has left directional; no brakes; Tahoe ok
Brake & right directional: Trailer has LEFT directional; no brakes; Tahoe ok
Lights & left directional: Trailer has left directional; no tail lights; Tahoe ok
Lights & right directional: Trailer has no lights; Tahoe has tail lights, but right directional stays on and does not blink
Both trailers have the same performance.
The Tahoe wiring has never been damaged or under water, and has worked fine for five years.
Can it be the right tail light module on the Tahoe? Wiring harness?
#38 of 63 Re: 2004 Tahoe Trailer Wiring Problems [rwag1945]
Sep 05, 2009 (10:21 am)
You have too many variables to solve, the way you are testing.
First, I would eliminate any trailer issues (mis-wiring, bulbs, or grounds) as possibly being the problem. To do this, you need to have a separate source of power to manually test it out (don't use the Tahoe trailer connector). You can use either a standalong battery, or build yourself a test power source with a cigarette lighter plug, some wire, and a couple alligator clips.
Powering from the cigarette lighter, connect to the different wires of the trailer and verify that each one is working exactly as it is supposed to. Verify that the correct filament of the bulbs (if you have the assemblies which use dual filaments) are lighting. The bright filament when a brake/turn is powered, the dim filament when the running lights are on. Verify also that you don't have any bulbs where the filaments are broken and crossed over onto the other filament. This will also verify that you ground back to the bulbs is good as well. Only after you are absolutely certain that the trailer is wired and working correctly, do I plug into the back trailer connector.
It is much easier to troubleshoot trailer wiring issues this way. In the first steps you eliminate the truck from being the source of any problems, until you absolutely are sure the trailer is correct. This then eliminates the trailer from being the source of the problem when you eventually connect them together...proving that you have a tahoe problem or not.
#39 of 63 99 tahoe electric trailer brake wiring
Dec 01, 2009 (4:59 pm)
I found out that this truck has a brake stoplight connection for attaching my trailer brake control, but is there somewhere to hook up the brake wire? My truck does have the blue and red wires at the light hook up. Any ideas?
#40 of 63 4 pin or 7 pin?
Dec 26, 2009 (1:00 pm)
First off are you using the factory 7 pin connector or an aftermarket 4 pin? These hook up differently and the four pin doesn't have a connection for electric brakes
Testing this can be a headache and time consuming and many times due to a bad ground if it occurs on most lights.
Kiawah above has posted the best manner to find the faults.
#41 of 63 Pulling 3900 lb travel trailer with 2008 Suburban LT
Jan 04, 2010 (3:08 pm)
I am pulling a 3900 lb travel trailer with my 2008 Suburban. It has the 5.3 liter V* with the 3.73 rear end. The book shows it rated at 7100 lbs for trailer towing. I recently pulled it over 2000 miles from Louisiana into the North Carolina mountains. Pulled a lot on the Blue Ridge parkway. I had no problems but my temp on the transmission did get over 220 on 1 or 2 occasions and I immediately backed off. When I got home I purchased a transmission cooler from GM since I found out I only had the radiator cooling. The only time I had the temp issue was climbing one steep road and once heading into a head wind and trying to drive 60 to 65 miles per hour. I recently emailed a transmission shop about what he thought and he said that there have been problems with the transmission in these. He thought that I was over my limit but I am barely at 1/2 what the book says. I was trying to stay well below what the book says anbd now I am wondering if I am pulling too heavy a load. Someone also suggested driving in a lower gear, but I don't want to drive across country in 3rd gear. Does anyone have any reasuring words for me so that I can relax in pulling a 3900 lb travel trailer. It was suggested by the transmission guy that I install the cooler and service the transmission every 30k miles. have I bought a Suburban with a weak transmission or are they reliable when towing? Thanks for any words.
#43 of 63 Re: Pulling 3900 lb travel trailer with 2008 Suburban LT [lucienl]
Jan 04, 2010 (4:47 pm)
I'd be sure to buy an extended warranty, if I was doing the trailering you do.
#44 of 63 Re: Pulling 3900 lb travel trailer with 2008 Suburban LT [kiawah]
Jan 04, 2010 (8:59 pm)
Well, I have purchased the 100k bumper to bumper and the vehicle only has 32k on it. The powertrain has the 100k warranty anyway. I have only pulled this trailer once since I bought it in October. I would only pull that distance probably once per year. My main concern is that I am pulling too heavy a load for a Suburban with a 5.3 liter. I believe the transmission is the 4L60E. I know it's the 4 speed and the rear end is the 3.73. The book shows 7100 max trailer weight which is considerable more than the 3900 I am pulling. I realize you have to take account for cargo, but I am not loading it up hardly at all. Leaving the water tanks almost empty till I get where I am going. I am just trying to see what people's experience has been with the newer Chevy Suburban transmissions. Thanks.
#45 of 63 Re: Pulling 3900 lb travel trailer with 2008 Suburban LT [lucienl]
Jan 05, 2010 (10:35 am)
I had a 2008 Suburban LTZ with the 5.3L and 3.73 rear end 4X4 and tow package (trans-cooler, etc). I towed approx 5K-6K lbs back and forth from OH to FL with no issues. Used the trailer mode. If I tried to stay on the gas to keep at 70-75 MPH, RPM ran in in 3200-3500 RPM range (3rd gear) and gas milage was terrible (<8 mpg). However - transmission temp never was an issue. I now have a 2009 2500 LT 4X4 (6L, 6 speed, and 3.73 rear end, and trans-cooler, etc.) and tow approx 9K - 10K lbs back and forth from OH to FL with no issues. Used trailer mode. Run in the 75mph range at approx 2200 RPM range and averaged just shy of 10 MPG. Trans temp never was above 150. Looked at 2007 2500 with 4.1 rear end - gas milage was terrible all the time, and RPM towing was back over 3000 RPM. If you are only pulling 4K lbs - you should not be having any issues ... Very happy with my '09 2500 towing ability ...
#46 of 63 Re: Pulling 3900 lb travel trailer with 2008 Suburban LT [zboater]
Jan 05, 2010 (12:33 pm)
Thank you for your reply. I am going to install the cooler before I tow again. I actually averaged about 10.5 to 11 mpg for the whole trip with the mountain driving included. I really had no issues other than the temp going a little high a couple times. I had some people tell me that 220 was not too high and the computer would shut the thing down if it got too high. Interstate driving at 60 to 65 was between 200 and 210. The dealer service tech said he wouldn't even worry about it but a cooler wouldn't hurt. I am not sure how yours was at 150 because GM says the normal operating temp is 180 to 200. I am reading mine with the onboard display that came on the vehicle. I have heard that depending on where the temp is sampled has something to do with what a guage may show.