Welcome to the forum @mcmopar .

Step back a bit and tell us what you've checked so far to get us the the no power status.

I'm including a link that we share with new folks to check out. Follow the steps and help us help you.

A better way to get help when posting on the technical...

I think there are a few things members here can do to help improve the speed and accuracy of which help is attained in diagnosing problems. Too often I see posts asking for help, but not providing any (or enough) information about their vehicle. I mention this, because there is more than one...

www.wranglerforum.com

 

I haved checked for power at the switch, changed switch, still nothing. Fuse is good at fuse block, and have power coming to that. Is there another relay that I dont know about?

 

Check out Got it at last's signature. In his signature he has a link to Factory Service Manuals (Jeep Manuals). Click on that link and then click on the FSM that applies to your year Jeep. The electrical schematics should be in the electrical troubleshooting section. The schematics will tell you what wire runs from the fuse panel to the headlight switch. That wire should be hot at all times.

Let us know how it goes.

Good Luck, L.M.

 

I am looking at page 505 but not really understanding where the power comes from. I can only follow the red wire so far.

 

Fuse #8 20a is your headlight fuse
S/B a 12ga red hot wire to headlamp switch that is always hot. If you do not have 12v there but do coming out of fuse block its a bad fuse or connection pin at fuse block.

 

In the 89 wiring diagrams on pages 1895 and 1896 of the 89 FSM you will find the schematics.
My pics.

 

Thanks, I didnt go down far enough. Correct I have power at fuse block but none at switch. Is it common for this to happen,

 

Also none of my fuses have numbers on them.

 

Post a pic of your fuse block. We can tell you which fuse is #10.
Have you checked all the fuses with a test light rather than visually?

Good Luck, L.M.

 

Fuses can corrode and not look burnt. As posted above, using a test light or volt/ohm meter is the best way to know for sure.

Additionally, you can have a broken pin in the fuse block or fuse not seated completely.

So yes, it does happen. Ask L.M. he had a couple pins in his fuse block a while back that required some replacements.

 

Here it is

 

Here’s a link displaying the relevant fusebox’s “contents”.

Looks like someone previously installed a 25A fuse in #8.

Rob

Fuse Box Diagram Jeep Wrangler (YJ; 1987-1995)

Fuse box diagrams (location and assignment of electrical fuses and relays) Jeep Wrangler (YJ; 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995).

fuse-box.info

 

No power to fuse #8. I will unbolt it and look at it tomorrow I hope. My turn signals still work, but they blink slow.

 

In my 1987-1988 (Page #696) and in the 1990 FSM (page #342), the headlight switch is wired direct from a fusible link connected to the starter solenoid (1987) or the starter relay 1988 and 1990.
I've hesitated to post this because it conflicts with posts by members that are more knowledgeable than I am.
I'm aware that OPs Jeep is a 1989. The above post by Anvilrob shows the #8 fuse as power to the headlight switch. I believe that circuit is for other lighting (turn, park and tail lamps) as shown in my '87-'88 FSM and the '90 FSM in GIAL's signature.
In order to help the OP suss out his headlight problem, I ask other posters to confirm or reject what I found. In my FSM the fusible link is green and connects to a 12 Gauge red wire running directly to the headlight switch.

If I was OP, I'd check for power at the 12G red wire, terminal "C", (not the thinner 16G red wire, terminal "E") at the headlight switch. If the heavier 12G red wire had power, I'd open the switch and clean the contacts. Then, reassemble with all the contacts covered in new dielectric grease. If after cleaning the innards of the headlight switch the headlights still don't work, I'd replace the switch.
If there was no power at the 12G red wire, I'd check the fusible link at the starter relay. Look for a wrinkled or bubbly area between the starter relay and the 12G red wire.

No power to fuse #8 could be caused by a fried fusible link as stated in the above paragraph. Check the schematics in the '90 FSM (Page #342).

Let us know what you find.

Good Luck, L.M.

 

So I just got home and read the previous post from @Luckymac. I had to smile at his polite way of telling me I might have been off a little bit in my armchair diagnosis this morning. L.M. is correct. I pulled my functional #8 fuse and headlights stayed on, but running lights went out and I could hear the relay click off. One of the three Red wires from the trio of green fusible links is indeed wired directly to the headlight portion of the switch. The smaller red goes to the fuse and then relay for running and instrument lights. Reinstalling the fuse brought everything back to normal inside and out.
Given that a higher amperage fuse was installed and you have no lights I'm leaning to agree with L.M. that you are not getting power to the switch via the fusible link.
One last question. Do you have gauge cluster and speedo lamps. If you do, that would indicate that you are getting power on the switched positive side through the fuse and switch to the relay, but you may also have a bad relay up by the radiator, a bad ground to the headlights, or a problem in the switch itself. If you do not have gauge lights you likely do not have power to either side keyed of constant and you may have two bad fusible links.

Thanks L.M. for digging deeper for us. I hate reading early in the day. Pictures are much easier to look at.

@mcmopar keep digging and update as you can.

 

I assume these are the fusible links. How do you check them, they don't look like they come apart.

 

I have no lights if I disconnect the jumper wire. The only thing that works is turn signals. I have no power on either wire going to the switch,

 

You would have to stab the red wire and check for continuity at the terminal post with a volt ohm meter to tell for sure.
A tell tale sign though would be burnt or shriveled insulation on the actual link but not always the case.
Years ago I fried one on a chevy S-10. took me forever to figure it out. No internet back then. Lol
I can't blow up your pic on my phone enough to see the wires condition

 

I can't blow them up on my desktop either, but they look like fusible links. A VOM isn't likely to have a sharp enough point on the probes to pierce the insulation of the red wire where it connects to the link.
Terms wrinkled, bubbly, burnt or shriveled apply to what you might see where the insulation of the link is damaged.
A fusible link is a sort of fuse that's designed to be a "slow blow" type of fuse rather than an instant blow of a conventional fuse. It's usually simply a thinner gauge wire than the rest of the circuit. In this case it's an 18G green wire connected to a 12G red wire. The theory being the thinner gauge wire will fail at a known point if the circuit is overloaded or shorted rather than burning up the entire circuit.
Most home mechanics replace a burnt fusible link with something like this. Attach a ring terminal to one end and solder and shrink tube the splice to the 12G red wire.

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Let us know what you find.

Good Luck, L.M.

 

I sharpened a piece steel like a pin and checked for power, on the red wire side of the fuse, and there was power. I think I have to take apart the fuse panel and look in there.

 

In order to open the fuse block you have to disconnect the firewall plug by the brake booster. You can check for power at the red wire at E4. If there's no power there, the problem is between the plug and the starter solenoid. If there is power there the problem will be in the fuse block.

For easier access to the fuse block, I remove the gauge bezel and the tach. Then I can use a long bladed screwdriver to easily reach the two large phillips screws that hold the fuse block to the firewall. I find it's easier to work under the dash when I remove the drivers seat so that I don't have to bend and twist my poor old bod over the door sill. YMMV.

Good Luck, L.M.

 

I am still working at it just haven't gotten back to it yet, hope to today.

 

Make sure to check for power at E4 before going to all the trouble of opening the fuse block.

Good Luck, L.M.

 

Is it labeled E4.

 

There's a grid type pattern to how the wires are arranged. It's called a "pinout". Once you pull the engine side of the plug loose (there's a small bolt in the middle) you can see that on one side there should be letters and on the top or bottom you should see numbers. Follow the E row across to the 4 row. That should be a heavy red wire. Use your test light to confirm the E4 terminal is hot.
Let us know what you find.
You may have to wipe off the inside of the plug to see the numbers and letters. They're cast into the outer perimeter of the plug.

What you're doing is quite an adventure into the more detailed aspects of auto mechanics. Don't be shy about asking questions.
To confirm all the information in all the posts above or to aid you in understanding that info, look for a post by Got it at last. In his signature he has a link to Jeep Manuals. Click on that link and then click on the 1987-1988 Factory Service Manual. The index is on the left side and the schematics (along with the alpha-numeric pinout of all the plugs) are at the bottom of the index. 1987-1988 wiring should be the same as 1990.

Good Luck, L.M.