I bought a '78 Aspen last week and I'm trying to iron out some electrical issues. The first is the horn doesn't work. I noticed the horn was disconnected but when plugging it back in, it still did not work. I tried getting a voltage reading at the horn but couldn't get anything. I can't find the relay to test there, can someone tell me where that is mounted? I am thinking the horn started going off on it's own as some point when the previous owner had it and that is why it was disconnected, but I cannot be sure. Any ideas on where I test for voltage or what the cause may be?

Also, the speedometer and radio lights are out but the heater light panel's lights work. Could this be anything other than a bulb?

All the fuses are good. Any help or idea would be appreciated.

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1978 4 door Dodge Aspen, Super Six

The speedo and radio lights are probably bulbs. I would change all of them, especially if they're hard to get at.

I don't know that car, but the '74 Dodge manual (latest that I have) shows the horn relay on the fuse panel. You should hear it click when you press the horn button. You'll probably need to have your head under the dash, down near the fuse panel.

Good luck!

ATB

BC

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'64 Dart GT convertible, 64 Dart 170 2-door post sedan in faded blue and rust (the Az Dart) & a sixty THREE Dart 170 2-door post sedan in faded blue and rust. (future project)
Early Dart Disorder (EDD) is real, and I've got it!

Thanks for the tips. I'll take a look under the dash today for the relay. If there is no clicking is that the sign of a dead relay?

The bulbs will have to wait, the car needs a once over on about every part of it before I start to worry about the interrior

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1978 4 door Dodge Aspen, Super Six

Per my 1978 Field Manual the Horn relay is plugged into the fuse block (the block now integrates several items that were previously separate items under the dash in the A-bodies-seat belt/ key in buzzer, horn relay, etc...).

I would make sure that all the connections are complete (horn has it's wiring hooked up, the horn button has it's wiring hooked up...). You can run a 'hot wire' from the battery to the horn to make sure it's working-if nothing, time for a junkyard run. If the horn is toast but the relay is good, you will hear a 'click' from the relay when you push the button or use a jumper to make the connection.

-D.Idiot

Tested the horn with a hot wire and it works. No click heard from the relay.

Tonight the speedometer lights came on some how. It seemed a bit dim, although it's the only time I've ever seen them working. The temperature gauge starting working too. It's kind of bizarre. I know the car was driven very little before bought it and seems to have been sitting around all it's life. It's a '78 with only 68,000 miles on it.

I'm going to take the dash off this weekend. If the bulbs are not dead could it be a bad or tarnished seat for the bulb?

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1978 4 door Dodge Aspen, Super Six

The hot wire trick only tests the horn, the relay is bypassed. It's good to know that the horn works before putting in a lot of time troubleshooting.

Lights coming on and gauge starting to work make me think you have a ground problem from the instrument cluster to the metal frame of the dash. It might be loose screws, but more likely there is some rust or corrosion involved. If you pull the cluster and leave the wiring connected, nothing will work. To do that, you need a separate ground wire. And be mighty careful not to short any electrical point to the dash.

It might be better to disconnect the battery ground cable anyway and look for obvious problems on the cluster at a well lit work area. Tarnish, loose connections, rust and corrosion are possible. GENTLY polish the contact points (bulb seats, connections of the gauges to the circuit board, etc) with 600 or finer wet or dry sandpaper. Tighten screws gently but firmly, and use a bit of silicone grease at those points.

35 years since it was assembled, it would be surprising if there were NOT problems like those.

ATB

BC

_________________
'64 Dart GT convertible, 64 Dart 170 2-door post sedan in faded blue and rust (the Az Dart) & a sixty THREE Dart 170 2-door post sedan in faded blue and rust. (future project)
Early Dart Disorder (EDD) is real, and I've got it!