No exterior lights or dash accessories

Chuck

Sr. Member
Joined
Nov 24, 2006
Messages
208
Points
18
Location
Billings, MT
Make
Chevrolet
Model
Allegro motorhome
Year
1988
Miles
95,000
Engine
454
This a little out of the box, but I have a 1988 Allegro class A motor. It's got 95,000mi. With the 454 CID (carburated) and TH400 automatic. My question is the wiring. The only thing that works are the ignition and turn signals. I would like to know if anyone here knows what vehicle wiring harness they used in them. This is the fuse box, Instrument cluster and the pressed circuit board on the back. Any help would be much appreciated. 20220920_180157.jpg20220920_180208.jpg20220920_180132.jpg
 

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
7,578
Points
63
I have little info left from back then, but it seems Chevy vans were all EFI by '88, except one variant of the 350 engine. So, this beast may be built on a chassis earlier than '88.

W will try to help, kind of blind, but would need more details of the present problem. Did this just pop-up, or did you acquire the vehicle in this condition? The photos indicate this is a "basket case" that you are trying to revive. Does the engine crank and run?

It looks like it is a fairly simple system, so we should be able to help you sort it out just from general principles, but it may take a lot of Q & A!
 

Chuck

Sr. Member
Joined
Nov 24, 2006
Messages
208
Points
18
Location
Billings, MT
I have little info left from back then, but it seems Chevy vans were all EFI by '88, except one variant of the 350 engine. So, this beast may be built on a chassis earlier than '88.

W will try to help, kind of blind, but would need more details of the present problem. Did this just pop-up, or did you acquire the vehicle in this condition? The photos indicate this is a "basket case" that you are trying to revive. Does the engine crank and run?

It looks like it is a fairly simple system, so we should be able to help you sort it out just from general principles, but it may take a lot of Q & A!
I did aquire it like this. It does run and drive.
 

Chuck

Sr. Member
Joined
Nov 24, 2006
Messages
208
Points
18
Location
Billings, MT
I just used a test light and it looks like everything that is supposed to get power when the key is on, is getting power at the fuse box. But the accessories that are supposed to be getting constant power are not. I saw 2 solid red wires going into the back of the fuse box and one is getting consent power and the other is getting no power at all with the key on or off.16638568167853248311587328904378.jpg
 

Mobile Dan

wrench
Joined
Mar 1, 2002
Messages
3,889
Points
48
Location
Kentucky
The red wire in the pic..."snakebit"... is that the one with no power? If so, stick a pin in the hole and apply (fused) power with a jumper wire and see what happens.
And...have you tested for power to your cluster connector? At least one of those pins should have power with the key on.
 

Chuck

Sr. Member
Joined
Nov 24, 2006
Messages
208
Points
18
Location
Billings, MT
I just used a test light and it looks like everything that is supposed to get power when the key is on, is getting power at the fuse box. But the accessories that are supposed to be getting constant power are not. I saw 2 solid red wires going into the back of the fuse box and one is getting consent power and the other is getting no power at all with the key on or off.View attachment 11631
The red wire in the pic..."snakebit"... is that the one with no power? If so, stick a pin in the hole and apply (fused) power with a jumper wire and see what happens.
And...have you tested for power to your cluster connector? At least one of those pins should have power with the key on.
I put a pin in, with a test wire and hook the other end to an ignition power source on the fuse box and I got hazard lights, turn signals and when I turned on the headlights only the park lights came on and they were dim. But the headlights didn't work.
 

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
7,578
Points
63
Do you have the rectangular connector that mates with those PCB fingers at the lower-center of the cluster? What is that in the center of the cluster, with an orange rectangle around it?

For the lights, I would start tracing right at the specific light. The wiring will be simpler going from that end. Once you have each individual circuit known to be working, and the wires for it identified, figuring out that mess will be easier.

Is "Allegro" no longer in business?
 

Chuck

Sr. Member
Joined
Nov 24, 2006
Messages
208
Points
18
Location
Billings, MT
That orange rectangle in the center of the cluster is the brake light. Allegro is apparently the model. It was constructed by Tiffin motorhomes, and they are still in business.
 

Chuck

Sr. Member
Joined
Nov 24, 2006
Messages
208
Points
18
Location
Billings, MT
By the wiring diagram you sent me. I think the issue could be the fusible link to the consant power. Would I have to get another one?
 
Top