No headlights

[Nad_Yvalhosert]

Was more of a question as mine does.

Yours is a Vortec? The first slew of TBI trucks were very basic.
Luckily I get to compare my fleet, nearly side by side: '88, '89, '95, and '00. All 5.7's 3 TBIs and a Vortec.

 

[Nad_Yvalhosert]

I have power to brake, parking, turn signals, everything except headlights. Has to be that switch!

The high beam switch interrupts the low beam power when switching to high.
The actual switch is located at the base of the column, find and follow the rod coming from the t-sig lever, and check for power.

 

[thinger2]

Your headlight plugs are rotted and the wire behind them is rotted.
and your ground may be not good enough.
Maybe for several inches.
To test this cut your power wire several inches back from the plug.
Leave enough room to splice on a new pigtail harness.
Buy a new pigtail for the lights.
Check for power again making sure you have a good ground.
I think you have rotted light plugs and you are testing corroded contacts with about 4 to 6 inches of rotted wire behind them.
I think it is not under the dash at all.
I think it is the light harness plugs and corroded wiring

 

[Chockful93Blazer]

I was going to start my own thread but this one is the same problem as mine except I get no power at the lights at all. Long story short I’ve been snookered a bit by a someone telling me everything works and now I’ve spent the evening at Oreillya taking the whole light assembly off and finding nothing wrong. Changed the light switch and I get nothing. Stalk switch works the turn signals but nothing with the lights. How hard is it to replace? Or is there an easy bypass?

 

[1990Z71Swede]

I got the link below from user east302, when I had problems.
Headlights wiring is in the "1990 ...Wiring_Manual"

In my case it was the switch, I dont think it is the case here.

After the Headligt switch, Voltage goes to the dimmer switch( stalk on column) where it is split into Hi or Lo and after that through "C100/102" which I guess is the connector on the firewall. I too would suspect you are loosing your power on the way to or in the dimmer switch. Unless some one has installed relays, if so I would check them first.

I installed a relay (on the radiator support close to the battery) to keep my new switch alive much longer, someone might have done the same on your truck, as Schurkey pointed out.
And I was CRAZY enough to put a fuse on the relay feed
BUT I can think of atleast one other thing that is even more crazy....

88-98 Service Manuals

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