I've recently dropped a rebuilt carbed 350 in my 90 rs. This engine came from a 1970s chevy so it does not use the computer in the car. Before I rebuilt the engine the lights worked fine, but after we dropped the rebuilt engine in the lights went kinda wacky. Has anyone on here rewired their lights? I'm going to try to replace the dimmer switch mounted on the steering column to see if that is the problem, but any suggestions are appreciated!

Thanks,
Gabe

 

I basically just did the same swap, except I replaced a V6. The only problem I had with the lights is when I forgot to reconnect the ground behind the driver's side headlights. The lights in front were real dim and the wipers moved verrrrrry slowly, if at all. Turns out that the wipers and front lights share that ground and with it disconnected the headlights were grounding through my wiper motor.

Moral of the story: Whenever anything electrical goes goofy on you, check the grounds before anything else.

That being said, can you be more specific about what is acting up? I assume you are talking about the front lights(headlights/turns/parking)?

What makes you think its the dimmer switch? There is nothing about an engine swap that should involve/damage the dimmer switch.

 

Do you have the ground strap that goes from the motor/trans connected to the firewall?Could have been overlooked also.
IDK if everyone has this strap but thats how mine is.

 

I have mine connected from the passenger head to the frame rail. Works just fine for me. Firewall will work too, as long as you get a good clean connection.

 

Haven't checked the grounds yet... Just thinking that it may be a coincidence that the switch went out. I didn't really do a swap, just got the engine rebuilt from the block up. When we put the engine back in and tried everything out this is what happened.

-Driver side head light is VERY dim (almost completely out)
-when the brights are turned on the left front blinker light stays on and will not blink when I engage that blinker to the left
-The lights on the cluster come on and both my speedometer and tachometer go out.
-Also the fuel gauge stopped working after having the engine rebuilt.....

... Those are all the things I can think of at the moment. we didn't mess with anything under the dash really when we removed the engine to put it back in, but maybe my grounds aren't set right. I haven't tried the wipers with the lights on like suggested above but I'll have to check into that.

 

you definitely have a ground issue - there's nothing about a swap other tha grounds that would effect lights.

 

Well i'm hoping to fix that... soon. I have to re-tighten my transmission cooler lines because they loosened up and are leaking now. Haven't even driven her in almost 2 months... but then again its WAY too hot down here in NM to drive that beast! Once it starts cooling down I'm hoping to get the little things fixed so I can take her out like she needs to be!

 

Check right behind the headlights on the driver's side. There is a small black wire in the headlight harness that has a ring terminal on the end that should be grounded to the radiator support. The passenger side has one as well. They are the grounds for the front lights on their respective sides of the car.

When you say the speedo and tach go out, do you mean they stop working? Or they don't light up?

 

I know which grounds you're talking about... I'll check into those. As for your question on the tach and speedo... Half the cluster lights up when the lights switch is on and both the tach and speedo stop working.... don't register anything. Sometimes the tach needle will fall to the red line side (mainly if I turn the lights on while driving). I'm not so worried about the tach because I replaced it with an aftermarket gauge but I would like to keep my speedo working.

 

IIRC, the gauge lights get power from both sides of the dash. Left connector powers the lights on that side, and the right connector powers the lights on that side. I believe the speedo and tach get their power from their own side as well as have their own grounds so I don't think the dash lights are shorting to those connections. My guess is that the +12V for the lights is shorting to your VSS signal to the dash. I believe the VSS connection is on the right side connection. Which side are the lights not working on? If its the right side, check the printed circuit on the back of the dash cluster on that side between the connector contacts and the tach and the VSS. If its the left side, check the circuits between the connector and the speedo.

I would also try pulling all the light bulbs, even the ones for the warning lights and see if the tach and speedo still die when you turn the lights on.

 

Alright... just wanted to let everyone know that I got my lights figured out... It was a ground issue on the driver side of the engine compartment.. Completely my bad whenever I hooked everything back up after painting the compartment when we had the engine out. However, I still lose power to my Speedo when I turn my lights on... any ideas on that?

 

You must have spliced power/GRD to the buffer box off some wire relating to the lights

Speedo should have nothing to do with the front lights either