Ask an expert

I have a 1999 Toyota Camry GX sedan, last night I took it out after dark for the first time in a few weeks and found that the headlights are not working when dipped, it's due for a warrant in a couple of weeks and I know it will need at least 2 tyres replaced to pass, which will already be a struggle to pay for so I'm looking to fix this as cheaply as possible, I've checked the bulbs and they appear to be fine, everything I have been able to find says that it is likely a problem with either the relay or the switch, any tips on how to tell which and how to repair myself would be greatly appreciated.
Just to clarify all the other lights are working fine, full beams are fine, as are the running lights side lights etc. it's just when I put them on dip.

I'd agree that the problem is most likely to be the headlight relay or the dip switch. The easiest thing for you to check will be the relay. All the relays are located under a black plastic cover in the engine bay (on the passenger's side).
On the underside of the cover, the relay locations should be marked. Locate the low beam relay and try swapping it with another similar relay (high beam for example). If the lights work with another relay, you'll just need to buy a new relay.
If this doesn't pinpoint the problem, it gets more tricky. You really need experience working with electrical systems to do any further diagnosis - tracing circuits, testing power feeds in and out of the dip switch etc. This will involve removing the steering column surround and other parts. It's not advisable for you to do this if you're not experienced. In particular, you need to be very careful not to probe any wires or terminals that could trigger airbags or damage other systems so it's really a job for an auto-electrician.