Cruise Control 2008Tahoe Ather Replaceing Brake Switch
January 1st, 2017, 12:18 PM
#1
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Cruise Control Ohm Values 2008 Tahoe -- After Replaceing Brake Switch
Problem--cruise control "set" switch will not engage. Have confirmed the cruise control contacts from the brake switch are "made" when the brake is in the unapplied position and "open" when the brake is applied. There are no DTC's set, system voltage is between 9-16, and the antilock brake/traction control system has not been active when trying to set cruise control.
I want to confirm the operation of the cruise control switches and have the steering wheel removed from the vehicle. Taking ohm readings from the steering wheel harness to steering column connector at the grey to red wire or "A" to "E" on the connector and with the middle cruise control switch depressed or "on"---6,810 ohms resting and 2,310 ohms when the "set" switch is depressed. These values go to "open" when the middle cruise control switch is "off'. Question-are these values correct for engaging the cruise control?
I want to confirm the operation of the cruise control switches and have the steering wheel removed from the vehicle. Taking ohm readings from the steering wheel harness to steering column connector at the grey to red wire or "A" to "E" on the connector and with the middle cruise control switch depressed or "on"---6,810 ohms resting and 2,310 ohms when the "set" switch is depressed. These values go to "open" when the middle cruise control switch is "off'. Question-are these values correct for engaging the cruise control?
Last edited by jimmy283; January 1st, 2017 at 1:58 PM. Reason: Grammatical and adding clearifications
January 1st, 2017, 2:58 PM
#2
if any codes are set, they will be stored in the bcm so a basic code reader will not access body codes. a full function scan tool is needed.
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the switches use a mux system which is a resistive ladder. It can be checked with a scan tool without having to remove anything. the values, if you want to ohm them out are:
off- open
on- 6.6 - 7.0 kohm
set- 2.1- 2.5 kohm
resume- 3.6-4.0 kohm
cancel- 1.3-1.7 kohm
anything spliced into these wires, corrosion will change the resistance and the signal voltage
=
the switches use a mux system which is a resistive ladder. It can be checked with a scan tool without having to remove anything. the values, if you want to ohm them out are:
off- open
on- 6.6 - 7.0 kohm
set- 2.1- 2.5 kohm
resume- 3.6-4.0 kohm
cancel- 1.3-1.7 kohm
anything spliced into these wires, corrosion will change the resistance and the signal voltage
January 1st, 2017, 6:36 PM
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Thanks tech2 for this information.
So it appears my switch is operating correctly as it is in the range of your values.
A P0573 had been set but without a MIL. I cleared the DTC's but you are saying that there is additional information in the BCM that my Innova 31403 scanner either cannot see or I do not know how to access it?
So it appears my switch is operating correctly as it is in the range of your values.
A P0573 had been set but without a MIL. I cleared the DTC's but you are saying that there is additional information in the BCM that my Innova 31403 scanner either cannot see or I do not know how to access it?
January 2nd, 2017, 9:34 AM
#4
Vehicles set Powertrain, body, chassis and undefined codes. the innova can only access P or powertrain faults and some U codes. Your scan tool is blind to chassis and body dtc. the cruise is controlled by the bcm. A scan tool that can access B or body codes is required to read these codes.
Since you had a p0573, I would do some component testing of the brake switch. Its a pretty common part to fail.
Since you had a p0573, I would do some component testing of the brake switch. Its a pretty common part to fail.