Transmission 4l80e

[Crik13]

Transmission 4l80e still in limp mode...

So, I finally had time to work on the m1123 again. I tried to reset the relay and that did not seem to reset/ no change. So I changed the dual switch at the brake pedal, not sure how to adjust it, so I tried it at one end of the adjustment and at the other and that did not make a difference either?
Any ideas? Thank you for all uou help in advance!

 

[Mogman]

What codes are coming from your TCM?

 

[springer1981]

Transmission 4l80e still in limp mode...

So, I finally had time to work on the m1123 again. I tried to reset the relay and that did not seem to reset/ no change. So I changed the dual switch at the brake pedal, not sure how to adjust it, so I tried it at one end of the adjustment and at the other and that did not make a difference either?
Any ideas? Thank you for all uou help in advance!

The adjustment is for the brake light switch. Adjust it until the brake lights come on with a light pressure to ensure your brake lights work when you hit the brakes.

 

[Crik13]

The adjustment is for the brake light switch. Adjust it until the brake lights come on with a light pressure to ensure your brake lights work when you hit the brakes.

Thank you

 

[Crik13]

What codes are coming from your TCM?

I can't get the transmission light or transfer light to work. My other dash lights work. I put the wire ina and e on the transmission box and nothing happens.
Thank you for your help!

 

[Mogman]

I can't get the transmission light or transfer light to work. My other dash lights work. I put the wire ina and e on the transmission box and nothing happens.
Thank you for your help!

Well then that is the first thing you need to figure out, sounds like you have a wiring problem or possibly no power at all to the TCM.
Without the codes you you are just pissing in the wind, no need to go any farther until you figure out why you cannot get codes

 

[Crik13]

What codes are coming from your TCM?

My transmission and transfer case lights do not work, the dash lights do. I connected a wire at a and e on the tcm and a dummy light and had no response at the light or at the a and e ports.

 

[Crik13]

Well then that is the first thing you need to figure out, sounds like you have a wiring problem or possibly no power at all to the TCM.
Without the codes you you are just pissing in the wind, no need to go any farther until you figure out why you cannot get codes

Thanks for your help, I will keep ya posted.

 

[Action]

A is ground
D is 12 v
see if you get voltage between those 2.

 

[Crik13]

A is ground
D is 12 v
see if you get voltage between those 2.

Action
There is no power to the transmission. At the tcm, the main wire harness do you know what wire code is the power?

 

[Milcommoguy]

Action
There is no power to the transmission. At the tcm, the main wire harness do you know what wire code is the power?

Time to say... see the TM's.

Your friendly librarian. This might work???? Redirect to the HUMMER Knowldge page... BUT can be helpful for info related to HumV. Let your finger to the searching.

Redirect Notice

OR



Might just have to stay after school, CAMO

 

[Crik13]

Thank you

 

[Crik13]

Is the wire 290/291/537 A connection at the + terminal ?

 

[Mogman]

You need to look closely 290B is hot with 12V all the time, carries 12V to the relay,, 290C is switched 12V from the relay
Then it goes to 4 different locations, the light, the stop light switch, the transmission and the TCM under different wire numbers, use the link as the posted schematic is not easy to read.
EDIT, this is 12V not 24V
The relay has a 24V coil that is hot (relay on) in the run position

 

[Mogman]

If the light is coming on when you put the switch in the run position then the relay is working, you need to check voltage to the other three locations.

 

[Crik13]

If the light is coming on when you put the switch in the run position then the relay is working, you need to check voltage to the other three locations.

Neither one of the lights bt gear shift come on.

 

[Mogman]

Neither one of the lights bt gear shift come on.

Do you have 12V on pin 3 of the relay when the run switch is in the run position??? (290C)

 

[Crik13]

Do you have 12V on pin 3 of the relay when the run switch is in the run position??? (290C)

It reads 11.88

 

[Mogman]

OK, now see if you have switched 12V at the TCM wire 291D, pin i
You can also look to see if you have 12V switched at the brake switch wire 810A
and the trans. light wire 667B
how do all the connector pins look?

 

[Mogman]

Basically all you should need to get codes from the TCM are,,,,
Power to the TCM, a confirmed working trans light and confirmation that you are actually shorting the leads to get the codes.
if all of these are met and you still do not see any codes then you would start looking at the TCM itself.