93 chev Blazer

Headlamps Inoperative - Low Beams

Step

Action

Value(s)

Yes

No

DEFINITION: This diagnostic procedure should only be used if the high beam headlamps are operating properly and the low beams are inoperative.

1

Did you perform the Headlights System Check?
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Go to Step 2
Go to Headlight System Check

2

1. Turn the headlamp and panel dimmer switch to the ON position.
2. Move the headlamp dimmer switch to the LOW position.
3. Backprobe the headlamp dimmer switch connector with a J 35616-200 from cavity A to ground.

Does the test lamp light?
--
Go to Step 3
Go to Step 5

3

1. Remove the daytime running lamp relay.
2. Connect a J 35616-200 at cavity G5 to ground.

Does the test lamp light?
--
Go to Step 4
Go to Step 6

4

1. Re-install the daytime running lamp relay.
2. Backprobe cavity B at the high/low beam headlamp with the headlamp dimmer switch in the LOW position.

Does the test lamp light?
--
Go to Step 7
Go to Step 8

5

Replace the headlamp dimmer switch.

Is the repair complete?
--
Go to Headlight System Check
--

6

Repair the open in CKT 359 (PPL) between the headlamp dimmer switch and the daytime running lamp relay.

Is the repair complete?
--
Go to Headlight System Check
--

7

Replace the high/low beam headlamps.

Is the repair complete?
--
Go to Headlight System Check
--

8

1. Inspect for an open in CKT 12 (TAN) between the daytime running lamp relay and S120, repair as necessary.
2. Replace the daytime running lamp relay if no open was found in CKT 12 (TAN) between the daytime running lamp relay and S120.

Is the repair complete?
--
Go to Headlight System Check
--

93 Jeep Loredos didn't have daytime running lights from the factory. It has to be an after market set up so I would trace wires to power and ground. It probably has a connection to the headlight switch wires through some sort of solenoid.

there is a relay under the hood in the fuse/relay panel called drl, or daytime running lamps, that relay is most likely bad, a good way to tell is switch it with the high beam relay, if they come on you know thats it, if they dont, its the relay for the lowbeams, again switch it with the high beam relay and see.. either way i can tell you for sure one of those two are bad... but most of the time it is the daytime running lamps, or sometimes called driving lights relay. hope this helps you

First, be sure that the headlights are actually coming on. These cars have daytime running lights that use the headlight bulbs at a lower voltage. If the car is only using the daytime running lights, the tail lights will not be on with the headlights. The multifunction lever always turns on the high beams when you pull on it (it's called 'flash to pass'). Make sure the headlight switch is working, and also check the headlight circuit breaker.

The wiring for these headlights is complicated. The body control module (BCM) controls whether the headlights should be on or off depending on the ambient light sensor readings. Your headlight switch should override this if switched to on - if it doesn't do this, the headlight power relay may be faulty.
The daytime running lamps (DRLs) are also controlled by the BCM and a DRL relay, also controlled by readings from the ambient light sensor. If they will not come on, the DRL relay may be faulty.
However, the root cause could be a fuse, faulty light sensor, headlight switch, or BCM. I would start by checking the fuses and checking/replacing the two relays.

Yes. These are called DRL's or daytime running lights. It is law that vehicles manufactured after 1985 must have low amperage lighting on while running.

replace the main headlight switch and the connector to that switch, the connector can be obtained from the dealer only in most cases.

If you have daytime running lights but when you turn on your regular headlight on they do not come on. Take the bottom of your steering column off (Two Small Screws) and look at the back of your turn/dimmer switch make sure that the light blue wire is connected. The wires will break off after years of raising and lowering your steering column.

although the underhood relay panel is common, I'd check your headlamp bulbs first, these are cheaper than the fuse box. The daytime running lights work off the high beam circuit, thus, a blown highbeam bulb could be the culprit, the fusebox solution was more common on 2001 and up modles, although it's a definite possibility.

Sounds like the bulbs need replacement. The high beams are separate from the low beam/daytime running lights.