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Is the anti-theft light lit on the instrument cluster ? Won't start how ? When you turn the key to start , what happens ? Nothing ? This would be a No crank - no start condition . Now if you turn the key to start and the starter engages and spins the engine and it doesn't start an run , this is a engine cranks no start condition ! Now which is your problem ?
There are two fuse's IGN A fuse 40amp and IGN E fuse 10amp ,both are located in the under hood fuse/relay box . Also there is starter relay located in the same under hood fuse /relay box . There also is a crank fuse 10amp in the under hood fuse box . Besides the fuse's and relay ,the ignition switch or the PNP - park neutral position switch could be bad . Testing the whole starter circuit should be done ! How to voltage drop test starter motor circuit
If the battery is good, then there should be power at the starter solenoid. The solenoid is connected to the starter.The solenoid is energized by the ignition key. When the key is turned, the starter solenoid allows power to feed the starter. Try tapping the starter solenoid while turning the key. Have a friend help and use something non metallic to tap the solenoid. Good luck!
Does your key switch work good? Do the warning lights and gauges on the dash all turn on with key in on? That verifies the ignition switch has power. If not, check fuse #9 in the Power Distribution Center (under the hood). It is a 30 amp fuse, providing power to the switch.
Are the battery cables clean and tightly connected at the battery and starter and the battery ground connection?
There is an Engine Starter Motor relay in the Power Distribution Center, the only thing between the ignition switch and the starter. With key in start, power is sent from the switch to this relay, and if relay is activated by the PCM (engine computer), then power goes on to the starter solenoid on the starter, and starter should then operate and crank the engine. If you have a voltmeter, you could do some tests for power at the terminals the relay plugs into. There are only 4 terminals. Post back with comments, or if you need help with testing those terminals.
yes it could be just a wiring, fuse or relay problem. Most common is the starter relay in the fuse box, or a bad ground somewhere. If the relays, wires, grounds are all good, might just be the starer solenoid that is faulty, or the starter motor itself. In both cases nowadays, you will need to remove the starter to test either the solenoid or motor. Also might be a good idea to check if voltage gets the the relay in the fuse box when you turn the key, as contacts in ignition switch can be faulty. Just remove starter relay in fuse block and check the right pins with a voltmeter while a friend turns the key in the ignition. Hope this helps :)
Do you have power on the small wire at the starter with the key in the crank position?
Something else you can do is pull the starter relay. One pin should have power all the time (power from the 50 amp fuse number 9). One pin should have power with the key in the crank position (power from fuse 10 via the ignition switch. The other two pins should be grounded. One goes to the starter solenoid and the other goes to the neutral safety switch.
Let me know what you find and I'll see what I can do!
Hi, the problem is either with the crank fuse, ignition switch, safety interlock or the starter relay. First check the fuse (in the instrument panel fuse box). Can you hear the starter relay click when you turn the key to start? You may want to probe the relay socket with a 12 volt test light to see if the ignition switch is working. If it is, there will be 2 hot terminals in the socket when the key is turned. The relay is in the relay box under the hood. Connect your test light clip to chassis or engine ground, pull out the starter relay, and have someone hold the key in the start position while you probe the relay socket terminals. If there are 2 hot terminals, replace the relay. If there is only one hot terminal, try bypassing the interlock switch. On a manual transmission, the interlock is above the clutch pedal. Pull the connector off it and connect the terminals in the connector using a large paper clip.
If you have an automatic, pull the connector off the range sensor and connect the green and purple wires using a large paper clip. I think it's on the tranny. See picture of it below. Please let me know if you have questins, and thanks for using FixYa.
Hi, diagnosing a no-start condition requires a logical approach to figuring out what might be preventing your car from starting. First, if the engine won't even crank over when you turn the ignition to START, your car obviously won't start. When you turn the ignition key to start your car, voltage from the battery flows through the ignition switch to the Park/Neutral safety switch and/or brake pedal or clutch pedal safety switch (you have to push the pedal down before the circuit will complete) to the starter relay or solenoid. When the relay or solenoid is energized by voltage from the ignition switch circuit, it closes a contact that routes more power from the battery directly to the starter to crank the engine. The starter motor spins, pushes the starter drive gear to engage the flywheel and cranks the engine. If the engine fails to crank, there is a fault in one of the components in the battery/ignition/starter circuit. Ten Reasons why you car won't start..
Low battery (Check battery voltage, recharge if low, or jump start with another vehicle or battery charger).
Loose or corroded battery cables (Inspect, clean and tighten BOTH ends of BOTH battery cables).
Bad starter relay wiring connections or ground connection (Inspect, clean, tighten wiring connections).
Bad starter relay/solenoid (Check for voltage at relay, if relay has voltage but there is no "click" when key is turned to start, replace relay).
Bad starter (Jump battery voltage direct to starter to see if it spins, or remove starter and have it bench tested at auto parts store).
Damaged starter drive or teeth on flywheel (Remove starter and inspect drive gear and flywheel teeth, replace damaged parts if necessary).
Bad ignition switch (Check to see if voltage reaches starter relay/solenoid when turn to start. If not, check for open P/N switch and brake or clutch pedal switch. Replace ignition switch if defective).
Open P/N safety switch, or open Brake Pedal Safety Switch (automatic transmission) or open Clutch Pedal Switch (manual transmission). Bypass switch with jumper wire to see if engine cranks, or use test light or voltmeter to check for voltage passing through switch when ignition is turned to start.
Engine seized due to bearing failure or internal damage (Use socket and long handle to see if engine can be turned by hand, if not engine is locked up).
Engine hydrolocked due to coolant leak from leaky head gasket (Use socket and wrench to see if engine rotates, remove spark plugs and see if coolant comes out or engine can not be cranked with plugs out).
did you check your fuses and relay for power a test light will work. start with the fuse first. the relay should have 1 power all the time. the other will with the key turned to start. rare for the switch to go bad. best of luck
If he had it started two times without the key , i would think it was the starter either . Do you an the guy who replace the ignition switch know how the starting system on your tahoe works ? Do you know what a neutral safety switch is ? Try moving the gear shifter to neutral an see if it starts then . That is if your tahoe has a automatic transmission . When you turn the key to the start position this sends a voltage signal to the PCM - engine computer which inturn will energize the starter relay , closing the contacts sending B+ voltage to the starter solenoid , spinning the engine over . Using a factory scan tool you would be able to see if that start signal from the ignition switch is making it to the PCM . Also would be able to energize the starter relay with the scan tool to see if the computer can energize the starter relay . You could also do testing with a DVOM - digital volt ohm meter . Find the PCM an connector 2 pin #59 , this is the circuit for start from ignition switch . Have someone turn the key to start , is there B+ voltage ? Find the starter relay in the under hood fuse box, pull it out an look on the bottom . You will see four sets of numbers 30 , 87 , 86 , 85 . If you take a piece of wire an jump 30 an 87 in the fuse box the starter will crank the engine , or spin the engine . If you do that and it won't start , cables , connections or the starter is the problem .
Today 11-12-08 my 2003 H2 Hummer would not start. Checked battery it ischarged. Cables tight. Tried to start with portable booster pak. No go. Tridto jump start with my wife's Suburban. Still no go.
When I turn the switch I hear a single click and that is it. No engine turning over. While trying to start with key the headlights go out. Out of ideas, Will take to Chevy garage in am. Will post solution.