1999 Tahoe Electrical Diagram Needed

[cqlink]

Anyone have a link to an electrical manual for our trucks? I have a '99 LT 5.7L.

I keep hearing a "clicking" noise coming from my inside fuse box when I start the truck. I looked under the dash and I can see a couple of splices which I think were made when the PO installed a VIPER alarm.

I have a few electrical glitches. Dome light override worked fine until I pulled the fuse for my daytime running lights. 4X4 indicator light switch works intermittently. 4X4 works correctly when I hit the switch but the indicator lights go on off. They usually won't stay on.

Not sure if any of this is related to the clicking I hear at the fuse box but thought I'd mention it in case anyone knows what's going on.

If anyone has the link or a page of the fuse box cartoon, please post.

Thanks!

 

[95TwinTT]

Has the Viper been removed?

 

[cqlink]

Not sure. The reason I say that is I'm using the Viper fob to open the truck doors but I haven't been able to locate it under the hood. PO or the dealer he got it from didn't have original GM fobs.

 

[lowpapasmurf]

You wont find a viper or any after market alarm under the hood. It will be up above the main wire harness under the driver side dash. Usually as high as it can go. Higher it is the harder it is to pull out in an attempted robbery. Anyway the wire diagram is as follows

1999 Chevy Tahoe

Alarm Lead	Wire Color	Wire Location
Constant 12V+	Red   		Ignition Switch Harness 
Starter 	Yellow  	Ignition Switch Harness 
Ignition 	Pink  		Ignition Switch Harness 
Ignition 2 	White  		Ignition Switch Harness 
Ignition 3 	Brown  		Ignition Switch Harness 
Accessory 	Orange  	Ignition Switch Harness (Heat/AC) 
Tach 		White  		Coil 
Brake Switch 	White  		Brake Switch 
Trunk Release 	Brown  		Switch or Driver's Kick Panel 
Trunk Pin 	Purple (-)  	4 Pin Black Connector Driver's Kick Panel 
Parking Lights 	Brown (+)  	Light Switch 
Head Lamp 	Yellow (+)  	Light Switch 
Factory Disarm 	Tan  		Keyless Entry right of Column 
Door Trigger 	Purple (-)  	Either Pin Switch 
Door Lock 	Light Blue  	Above Accelerator Pedal at Factory Relays 
Door Unlock 	White  		Positive Trigger 
Horn Wire 	Black (-)  	Steering Column 
Windows Up 	LF=Blue, RF=Light Blue, LR=Green, RR=Light Green 	 
Windows Down 	LF=Brown, RF=Tan, LR=Purple, RR=Purple

Oh and here is the Radio Pinouts as well.

Lead		Color
Constant 12V+	Orange 
Switched 12V+ 	Yellow 
Ground 		Black 
Illumination 	Gray 
Dimmer 		Brown 
Antenna 	Right Front 
Front Speakers 	6 1/2" Doors
Left Front (+) 	Tan 
Left Front (-) 	Gray 
Right Front (+) Light Green 
Right Front (-) Dark Green 
Rear Speakers 	6 1/2" Rear Doors
Left Rear (+) 	Brown 
Left Rear (-) 	Yellow 
Right Rear (+) 	Dark Blue 
Right Rear (-) 	Light Blue

Splices under the dash on the main harness are normal for after market alarms of any kind. The clicking you hear is the relays for that alarm. Usually there is a relay for lights, remote start, Window roll up/down or start kill. These relays will click at different times as the electricity is passed to open or close the circuit. Chances are the relays are in the alarm brain or attached to it and that alarm is "behind" your fuse panel up under the dash.

TIP:
Easiest and most comfortable way to see it is to lay your driver seat back all the way down and then lay upside down in the seat with your head under the dash. Remove any lower dash plates or covers and look up inside. Should be a black box and may or may not have black relays attached to it.

 

[cqlink]

Thanks. I got up under there yesterday and found most of it.

"Clicking" is coming from the relays you mentioned AND what I believe is the TCCM (small stainless box under the dash with 9-pin connector).

Looks like PO had the Viper in it with a decent sound system. I found what looks like a Sirius box plug-in cord dangling down there. It appears he pulled out the head unit and FUBAR'd the wiring.

VIPER key fob just stopped locking / unlocking doors. I figured out how this VIPER is programmed and tried to reset but fob still won't work. I could not get the VIPER to "chirp." I only get horn beeps. Not sure if the alarm unit was ever installed or just hooked to the horn and door locks. I opened the overhead compartment where a garage door opener can be stored and found disconnect wires there as well. A sticky note was up there explaining the VIPER was wired there to open a garage door.

Unfortunately, I'm not a great electrical guy. Here's what I have:

1) 4X4 indicators light works intermittently.
2) Clicking at TCCM (when it doesn't click - indicator lights work. 4X4 still engages with or without clicks.
3) F'd up VIPER / wiring won't open/ close locks.

Can anyone tell me what wires come from the door locks to the VIPER "brain" under the dash? It looks like there's an aftermarket alarm wiring harness down there with the red VIPER LED and the valet button dangling from a wire.

I love this truck but I'm now out $1600 and counting bringing it back up to specs!!!!!

Any insight greatly appreciated.

 

[cqlink]

Figured out the VIPER issue. Connector to the "antenna" actuating door locks had poor contact. Got the locks to work with VIPER fob. Discovered remote start feature was intact and that works too!

If anyone can shed some light on the TCCM and the indicator light switch issue, many thanks. Cheapest I could find a TCCM for under the dash was $210. Looks like the switch is around $40.

Any way to tell whch one i need? I don't know how to pull the codes with the "jumper" method (unless anyone has a link).

 

[lowpapasmurf]

I could not get the VIPER to "chirp." I only get horn beeps.

This is common is some applications. Keyless entry without an alarm or an application where an aftermarket alarm can mimic a factory alarm. The alarm brain can be set to run a siren, or a horn and in most cases never both. Although, there are always exceptions to the rule. If you do not see an alarm horn mounted in our around the engine bay then there is most likely no siren "alarm horn" so you will never get a "chirp". DEI the manufacturer of the Viper alarm uses a very standard color scheme for all of the their alarms. ie Clifford, Viper, Valet, Hornet, Python ect. If you follow the brown wire from the alarm harness it will go to the horn (Black wire at steering column) or a siren or both separated by a pair of diodes to isolate the circuits. If you have more than one brown wire which is possible it will depend on which harness on the alarm brain the brown wire comes from but lets tackle that later. I doubt this is a remote start alarm so you need not worry about that.

A sticky note was up there explaining the VIPER was wired there to open a garage door.

Anything can be wired to an extra channel on an alarm as long as you know how to use it. Relays can be used to funnel extra power and resistors can be used to buffer power to use any electronic device. Chances are the PO had one of the extra channels set up to apply power to the circuit within the garage door opener. Personally that's a bit odd but to each his own.

1) 4X4 indicators light works intermittently.
2) Clicking at TCCM (when it doesn't click - indicator lights work. 4X4 still engages with or without clicks.

Trace the wiring from the light back to the fuse panel. There may be a short, splice, or cut. Also try replacing the bulb. May just be a bad filament.

Can anyone tell me what wires come from the door locks to the VIPER "brain" under the dash? It looks like there's an aftermarket alarm wiring harness down there with the red VIPER LED and the valet button dangling from a wire.

Once again DEI uses a standard set of colors for their alarm harnesses. The valet switch is used for programming and to take it in and out of valet mode with the use of your ignition key. The wires for the valet switch are almost always gray and gray/black. The LED is almost always red and black or red/black and rarely connect to the main harness of the alarm. There are almost always side ports for those. The door lock harness is usually a 2 or 3 wire harness in the alarm or part of the main harness for the alarm. Green and Blue with an empty slot. Green (-) LOCK (+) UNLOCK output from alarm and Blue (+) LOCK (-) UNLOCK output from the alarm. So if you trace these wires back you can find out where they intersect the Light Blue and White door lock and unlock wires above the gas pedal at the factory GM lock relays.

TIP: Make sure you check all the door lock fuses in the fuse panel and verify that the lock and unlock work when using the buttons in the truck. If that doesn't work neither will the alarm. If I am not mistaken the 99 door locks are part of the cigar lighter circuit so if that failed the door locks are not working. Oh and here is another tip: before throwing a new fuse in make sure the cigar lighter is not short circuited behind the dash. If that lights up you will be doing a lot more then trying to figure out why lights a locks don't work.

 

[cqlink]

Good info on the VIPER!!! As mentioned, I was able to figure that one out (with some help!!!).

Back to the 4X4 indicator push button switch with lights:

There are four total lights (N, 4H, 4L and 2H). I got under there yesterday (really hard to see the back of the switch) and couldn't see a damn thing (switch too high up in the dash to see any wires).

Is there a way to pull the switch from the front of the dash?

Anyone know what color wire is running from the switch to the fuse box or is this switch running to the TCCM?

 

[lowpapasmurf]

Glad to hear it worked out. Guess it was a remote start alarm after all. Good deal. Sorry I cant help you with the TCCM.

 

[cqlink]

Thanks anyway. Excellent info.

 

[Monstar_est87]

Good info on the VIPER!!! As mentioned, I was able to figure that one out (with some help!!!).

Back to the 4X4 indicator push button switch with lights:

There are four total lights (N, 4H, 4L and 2H). I got under there yesterday (really hard to see the back of the switch) and couldn't see a damn thing (switch too high up in the dash to see any wires).

Is there a way to pull the switch from the front of the dash?

Anyone know what color wire is running from the switch to the fuse box or is this switch running to the TCCM?

Well have you tried removing the dash trim bezel..? Its basically a face mask for the dash... that should give u the best access to ur 4X4 switches...