GMC Sonoma - Popular Questions, Answers, Tips & Manuals - Page 7

Here is a link to the wiring diagrams for the car. http://bbbind.com/free_tsb.html

No high or low beams ? DRL ? Do you know how to check for B+ voltage with a volt meter ? Here is a web site for free wiring diagrams http://www.bbbind.com/free_tsb.html Enter the vehicle info. year , make , model an engine size . Then click on lighting under system , then click on headlamps . Click the search button , then click on the blue link . With a volt meter check power an grounds , Basic Electricity for Service Techs Ohm law Current Flow Opens Shorts Mastering Voltage Drop Testing with Pete Meier and Jerry Truglia Could be the headlamp switch or dimmer switch or blown fuse or a wiring problem etc.... testing the circuit is the way to a proper fix , not replacing parts or listening to someone on here say it this or that ! Test don't guess .

Sounds like you need to check out your local public library for a service manual to find the headlight relay, or in the owner's manual. Either one will help you determine which relay is which. It would be a good idea to take notes and that way you will know which relay controls what.

Possible the vacuum bleed-off to the switch you installed isn't allowing it to completely disengage. Pull the bleed-off line from the new switch and see if it works. could be just a tight spot/bent closed in the bleed-off line or the vent plugged.

possible problem head light relay or ground wires problem

Ignition switch wire connector.

This vehicle is 26 years old. You are bound to have mechanical problems with it. It sounds like looking for a newer model would be the best bet.

Sounds like more than one issue, not getting as hot as before, and slow to change from vent to defrost, The first I suspect you have a thermostat failing, not a big job or expensive either, remove the thermostat putt it in an old pan full of water bring it up to a boil, with a thermometer (I use a meat thermometer from the dollar store as you won't want to use it for food again) watch at what temp the thermostat pops if it doesn't pop at around 180 then replace it. second is the delay in switching from vent to defrost, again is not to expensive but is a bit troublesome as it sounds like you have a weak vacuum the louvers are moved by little dash pots the dash pot that moves the louver behind the dash could have a bad diaphragm or a crack vacuum line. not expensive just a pain to get at. a can of wd40 with the straw in place can help diagnose the problem if it changes properly when sprayed at time of activation (the line first then the dash pot) you will have found the bad boy Good luck

you changed the spark wires but did you change the plugs..and if its a carburetor check the distributer as well

Nice job in the details except for the make model and year.

The next time it will not start check the fuel pressure, I will bet you have none, the electric fuel pump is affected by temperature due to wear.

Your mechanic should know, he reset the light. Battery life can be as short as 24 months. You need to look at the age of the battery, if you bought a low price battery, it is a 24 month one. Check the cables on the battery and make sure they are clean and tight. You can get the OBD codes from any autoparts store, they read them free.

was the new ecm flashed to this vehicle --also what saused ecm to burn up you may have other connections --fuses--relays burnt up also need to test the obdll connector possible damage or blown fuse if the sonoma's accessory /cig lighter is out usually shares same fuse as the obdll port

Dude messed up your wiring. Have the dude fix it properly.

GM OBD Trouble Code 12

Sounds like an engine sensor, EGR valve or O2 sensor has failed. First thing to do is to look at the engine trouble codes to pin down the failure. You can usually borrow an OBD1 code checker from your local parts store.

I guess you have checked the trans fluid is up to full mark?

Try pulling up on turn signal switch.

What's wrong with it , have you had it checked for DTC'S - diagnostice trouble codes . The design of the passlock™ system is to prevent the vehicle operation if the proper ignition key is not used in order to start the vehicle. The mechanical key, in normal operation, will turn the passlock™ lock cylinder. The passlock™ sensor will relay the passlock™ data to the body control module (BCM). The BCM will determine the validity of the passlock™ data. The BCM will send a code password to the vehicle/powertrain control module (VCM/PCM). When the VCM/PCM receives the correct code the VCM/PCM allows the fuel injectors to operate normally. The passlock™ system requires the VCM/PCM and the BCM to communicate the various functions in order to operate. These functions transmit over the class 2 serial data line CKT 1807. For an explanation of the class 2 serial data operation refer to Data Link Connector Circuit Description in Wiring Systems. Telltale Indication Condition ON constant for 3 seconds, then OFF The bulb check occurs upon power-up (Ignition 1 and crank). ON constant for 3 seconds, OFF momentarily, ON constant/ignition OFF DTC (current) is set with the ignition ON (see DTC B2947, B2948, B2957 and B2958). ON constant/ignition OFF The TBC fuse is open or an open in CKT 1140 ON constant for 3 seconds, FLASH for 10 minutes, then OFF Occurs when a Passlock™ sensor has been replaced and the ignition switch has been turned from the OFF position to the CRANK position. This sequence occurs 3 times. FLASH with the ignition ON The Passlock system is in a tamper mode (see DTC B2960 and B3033). ON constant for 3 seconds, OFF momentarily, then ON constant for 10 minutes, then OFF Occurs when a new BCM or a new PCM/VCM has been installed, and the ignition switch has been turned from the OFF position to the CRANK position. This sequence occurs 3 times. ON constant for 3 seconds, OFF for 2 seconds, then ON constant The IPC is unable to communicate with the BCM. DTC B2947 Security System Sensor Power CKT Low DTC B2948 Security System Sensor Power CKT High DTC B2957 Security System Sensor Data Circuit Low DTC B2958 Security System Sensor Data Circuit High DTC B2960 Sec Sys Sensor Data Incorrect but Valid DTC B3031 Security System Controller in Learn Mode DTC B3033 Security System Indicates Tamper . Your best bet , take your vehicle to a qualified repair shop .