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H3 Passlock ignition switch sensor replacement

Marinmcgreevy

Member
Messages
11
Location
Mt. Lebanon, PA
Hi All,

thanks to to all of the info on this great forum I was able to diagnose and repair a crank-but-no-start issue on my Hummer.

The vehicle began to exhibit the symptom very intermittently about three months ago. It would crank but not start at first but waiting a while and trying again would usually happen. I did not notice the padlock warning light. I drive the vehicle infrequently so I just thought it was because it sat for periods between use. I did not exhibit the symptom after I started driving. It never did not start anywhere other than my driveway. Then one day I drove the truck to work and it did not start on the way home. Not happy. That’s when I started searching the forum for answers. It appeared to be the passlock system. I attempted to reset the system (30minutes?!?!) but what’s unsuccessful.

Ordered a new ignition switch sensor off of Amazon for $47.

The replacement is is very straightforward.
1. Remove the top and bottom plastic pieces on the steering column
2. remove the row Phillips screws that hold the sensor to the lock cylinder
3. Insert the key in the ignition and turn it to “on”. The sensor will pop off
4. Remove the wiring plug (push the tab in then pull off)
5. Install new sensor by reversing above steps.

Note: the new sensor comes mounted on a ignition lock cylinder and must be removed. To remove you must insert a screwdriver into the cylinder and rotate to mimic turning the ignition to “on” to release the sensor. You should not force the sensor.

You our will have to go through the 30 minute passlock learning cycle.

I took apart part the old sensor and found the tiny resistor was cracked and intermittent open circuit. 11 years of heat, cold, and vibration.

Thanks to all!
5F39D29E-8E3C-4207-9612-D2864D3FDE11.jpeg
The tiny resistor. Cracked. Sorry for the image quality. It is small!
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Turn clockwise to release sensor
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Part number
 

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alrock

El Diablo
Staff member
Messages
10,677
Location
Scottsdale
Excellent! Glad the forum could help you with this issue and provide you with a low cost repair.
 

chaynes

Member
Messages
16
Location
SEMI
You know, it’s funny you mention that it only occurred on your driveway. I had an issue recently where the H3 wouldn’t let the key out of the if ignition .... I thought it was so strange that it never occurred around town but only on my driveway! I would get home from work and have to wait a while before I could get the keys out. Turned out to be a relay with a corroded and broken terminal that made intermittent connection. It was the RAP (retained accessory power) relay. I still don’t have an explanation why it only occurred in my driveway but it was awfully considerate...


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