user635

Hello Everyone,

I've scanned the net and forums here looking for the answer to my Charge and Sensor lights not turning off when the truck is started. I've found bits and pieces, but not a complete answer for *my* truck. I have the painstaking details that may help some of you.

Truck: 1981 Toyota 4x4, SR-5, no PS, no AC, 22R, w/California smog and emissions ECU. I've owned it since 1993, so I have a good history with the vehicle.

Problem: On occasion over the last 5 years or so, the charge and sensor lights would come on when started. I would open the hood, and let it drop closed, or tap the voltage regulator (VR), and the lights would go out. The last 3 years or so, the charge light has only lit sporadically when I turn the key on. Truck charges normally.

2 weeks ago, charge/sensor lights came on and would not go off. Replaced VR, but no difference. Scanned Yotatech, and everyone said "It's your charge relay under the right side (passenger) of the dash." But some people mention they don't have one, and they don't… on the passenger side ;-)

Emissions computer (ECU): Some said this could cause the problem, didn't make sense, but I checked it out. On the connector pins, I found almost all of them with bad solder joints, and this made sense as the truck has been popping in the exhaust during deceleration for a few years. I repaired the solder joints, and went to reinstall the ECU, and there above it was...

The charge light relay - is on the drivers (left) side of *my* (ymmv) truck. I plugged in the ECU and started the truck, charge/sensor light still on. I tapped the relay, and they went off. Bad solder joint I figure, and at almost $100, worth a look. It comes apart really easy and quick. It had 3 bad joints, and one of the main spades felt loose. I resoldered everything and put it back in.

Everything now works correctly; no popping from the exhaust, charge and sensor lights go right out, charge light comes right on when I turn the key every time.

The truck runs WAY better, I only spent about 25 cents in solder, and it was an easy project.

Jim
1981 Toy 4x4

kawazx636

iTrader: (3)

Good to know! I just got done building my truck and at first my charge light would stay on because I didn't have the e-brake plug connected - they are on the same circuit so apparently the charge light will stay on if the e-brake isn't connected. For a couple weeks my charge light stayed off regularly, but this past week I noticed that it would blink to the beat of the radio and/or bumps in the road - made me feel like I had a disco right in my truck! The charge relay was going to be next on my list to check so maybe I'll look into this. Thanks!

enigmaT120

Good to know, thanks OP.

Now I'm wondering if I even still have the ECU in my truck, as it's mostly de-smogged.

user635

Dave, let us know what you find on your relay.

Jim

user635

Ed,

At this age, 34 years, I'm sure most have had the smog items removed. My truck is bone stock, 110k miles, so it's a good peak into a configuration you can troubleshoot with a FSM.

Jim

80Truck

Gonna jump into this thread, as I am having charging problems...
I've been looking for this charge lamp relay, and cannot find it!

Anyone with a 1980 truck/20R 4spd 4x4 can post a picture of where that thing is located?
Or does it even look the same as the one on User635's truck?

I've changed the voltage reg, tested the Alt, checked so many things that I'm forgetting what I have already checked...

Thanks,

user635

Your charge relay should look just like the one in my pic. It should either be below the glove box or directly above the hood release.

Jim

80Truck

Nope... not finding one anywhere... has me baffled...

user635

In my searches I'd found a few people who couldn't find theirs, and believed they didn't have one. Yours may be one of those trucks.

Try looking behind the radio. I remember one in a junk yard the had a couple of relays bolted to the firewall.

Good luck.

Jim

80Truck

Been sticking my head under the dash, looking all over... not seeing it anywhere... on the sides, the firewall, behind the radio, nowhere...
In the 83 FSM, there is a drawing that has a wire marked, an arrow to it with a description "without charge light relay"... now I am totally baffled....

80Truck

Never did find the charge light relay, so I'm going with my other plan, see my posts here: https://www.yotatech.com/forums/f114.../#post52274366