99 Yukon tranny/ guage issues?????

[Redeyeddog]

99 Yukon 115000 5.7 has developed problem with tranny????.....slow acceleration seems like its stuck in OD.......Tach/Speedo/gear indicator also do not work or do not work all the time. When they do work they dont seem to register proper RPM or speed. all problems happened at the same time so they must be related.... Any suggestions??????

 

[SunlitComet]

In cab fuse block, fuse #20 10 Amp. Condition please?

 

[Redeyeddog]

Thanks for the help!! Fuse is ok....replaced with new to make sure but same problems. Also I left out in earlier post that the check engine and check guage lights are on also.. Thanks again

 

[SunlitComet]

Yeah It sound like that fused circuit is dropping out somewhere long the way It power speedo, tach, check gauge circuits and tranny electronics. That will also give codes because the tranny becomes uncontrollable. Print out and follow the diagram below checking the terminals for that fuse and wiring before and after as well. To find the break somewhere. Any other questions feel free to ask. You have hit spot on to that circuit you just got to find where the fault lies.

4L60-E

Notes

nstrument Cluster Analog Schematics

Notes

Instrument Cluster: Analog Schematics (Gauges)


BTW that C100 connector in first pic is the bulkhead connector. And that fuse feeds off of ignition switch.

 

[Redeyeddog]

Think I found it!! Seems to be in the keyswitch.....lights go out and guages start to work when I give it a jiggle....taking steering collum apart now...thanks for the pics

 

[SunlitComet]

You may just need a new switch assembly.

---------- Post added at 05:43 PM ---------- Previous post was at 05:38 PM ----------

This should hook you up if you need a new one at cheap price.

http://www.amazon.com/ACDelco-D1414D-Switch-Assembly/dp/B000EQTZLU

 

[GIMike]

Killed my truck due to this issue....

Seems this a common issue with these as I've had this problem for a couple years now and it seems pretty common from the research I've done. The only problem is, I haven't seen much in the way of what people are saying have fixed it. Just a lot of suggestions as to what it could be.

My '99 Yukon is pretty much dead now because of this issue. The gauges the OP mentioned haven't really worked much for about the last year or so. I discovered that when the gauges weren't working, I didn't have a full first gear nor OD. Felt like taking off in a standard transmission car letting the clutch out realllly slow, not having much power and torque. When the gauges were working, I had full first gear and OD, and it was really quick to take off like it should be. That pretty much went away about that year ago, and I dealt with it as, due to a recent divorce and child support, I can't really afford to spend big bucks on all the possible different fixes out there.

I moved recently and the little covered uhaul trailer has now pretty much killed my truck. It was working OK at first, just took off slower than normal, but I had to make a couple different trips while hauling the trailer. I wasn't moving that far, less than 10 miles one way. Towards the end of the 2nd trip, it started shaking horribly, and had very very little power. Took forever to get up to the city street speeds of 30 mph. You'd think a 350 would have more power than this. I really wish I knew what the most common fix was, so I can have my truck back I'm having to ride my motorcycle every day and it's getting cold. 37 degrees on my way to work this morning. It's to the point where I'm about to see if somebody will trade me for anything that runs (even an 86 Yugo has a heater) so I can get out of the cold.

**edit** Just a couple of hours ago, I bought a new throttle position sensor from rock auto. They got em for $19. Hoping that'll take care of the shaking issue and it'll be back to where it was before I moved. Would love to have it running properly again though

 

[SunlitComet]

GI, start your own thread and give as many details as possible as to the problems you are experiencing. It will be easier and more accurate to help you individually.

---------- Post added at 12:21 PM ---------- Previous post was at 11:21 AM ----------

Red, forgot to add these:


Power Distribution Diagrams
Power Distribution

Notes

Power Distribution

Notes

Power Distribution (Cont)

Notes

Power Distribution (A, B & C Cont)

Notes

Power Distribution (F, G, H & J Cont)

 

[Redeyeddog]

Thanks SunLitComet.. didnt find any loose wires but after a few light thumps with a screwdriver on the upper switch assembly the problem is now temporarily fixed.......orderd the new switch assembly from the link you provided and will put that on and hopefully that should be the end of that. Thanks again

 

[SunlitComet]

If you have the passlock installed there may be some extra steps but I will pass them along when you get your part.