No headlights

89 XJ all the lights come on except the headlights. no highs or lows. Is there a relay or fuse that i should look for before I look at the light switch.

I really need to get myself some good books on the XJ.

First, I would pull the connectors from the back of the lamps and clean the contacts on the lamps and in the connectors, then use some dielectric grease.

Second, test for power and ground AT the lamp connectors, that way you will know the missing element.

After replacing the ECU I noticed no headlights. So going chase plugs under the dash.