1970-1980 GMC Jimmy Ignition Switch Guide and Diagnosis
Solve starting problems and electrical issues by understanding and replacing the right part in your classic Jimmy.
- The ignition switch is an electrical part on the steering column, not the mechanical lock cylinder where the key goes.
- Failure is critical as it can cause the engine to stall while driving, leading to a loss of power assist for steering and brakes.
- Replacement is a moderately difficult DIY job that requires lowering the steering column for access.
- You must confirm if your Jimmy has a tilt or non-tilt steering column before ordering a new part.
Is It the Ignition Switch or the Lock Cylinder?
Before buying parts, it's critical to know what has failed in your 1970-1980 GMC Jimmy. These trucks have two main components that work together.
- Ignition Lock Cylinder: This is the mechanical tumbler you put your key into. If your key is hard to turn, won't go in, or feels loose, the cylinder is likely the problem. 🎬 Watch: How to remove a 70s GM ignition lock cylinder
- Ignition Switch: This is the actual electrical switch located further down the steering column. It is activated by a rod connected to the lock cylinder. If you can turn the key, but nothing happens, or you have strange electrical problems, the switch is a common suspect.
This guide focuses on the electrical ignition switch.
Symptoms of a Failing Ignition Switch
A worn-out ignition switch can cause confusing issues. Because it controls power to nearly everything, symptoms can seem random. Look for these common warning signs:
🎬 Watch: A visual guide to symptoms of a bad ignition switch- No-Crank, No-Start: You turn the key and nothing happens. The starter motor is silent, even though the battery is good.
- Engine Stalls Randomly: The engine may shut off while you are driving, especially when going over bumps. This is a critical safety failure, as you will lose power steering and power brakes.
- Flickering Dashboard Lights: The warning lights and gauges on your dash may flicker, drop out, or not light up at all when the key is in the 'On' position.
- Accessories Don't Work Correctly: Your radio, heater blower, or wipers may not turn on, or they may cut in and out intermittently.
- Starts Then Immediately Stalls: The engine may fire up only while the key is held in the 'Start' position, but die as soon as you release it to the 'On' position. This indicates the switch isn't providing power in the 'Run' circuit.
Important Ordering Information
When ordering an ignition switch for your Jimmy, you must know if your truck has a tilt or non-tilt steering column. 🎬 See this walkthrough for replacing the switch on non-tilt columns The switches are often different between these two configurations. Always verify which column you have before purchasing a new part.
Choosing the Right Aftermarket Ignition Switch
For a vehicle of this era, aftermarket parts offer excellent value. OEM quality was simpler, and top-tier aftermarket brands often meet or exceed original standards. Here’s how the available brands generally stack up.
Brand Quality Tiers
- Premium Aftermarket (Standard Ignition): Standard Motor Products (SMP) is a highly respected brand in the automotive aftermarket with a long history of making quality electrical components. Technicians often trust this brand for its reliability and proper fit, making it an excellent choice for a durable repair.
- Standard Aftermarket (Rostra Powertrain): Rostra is a known manufacturer of various automotive parts. While specific reviews for their ignition switches on this platform are scarce, they are an established company in the aftermarket space.
- Economy Aftermarket (Replacement): This category includes various budget-friendly brands. While they are the most affordable, quality can be inconsistent. They can be a viable option for a quick fix on a limited budget, but may not offer the same longevity as a premium brand.
New Aftermarket Ignition Switch Cost for 1970-1980 GMC Jimmy
| Part Type | Price Range |
|---|---|
| New Aftermarket Ignition Switch | $20.77 - $55.28 |
| Estimated Shop Labor | $150 - $250 |
Cost estimates are for the part and labor only and do not include taxes, shop fees, or diagnostic charges.
A Note on Installation
Replacing the ignition switch on a 1970-1980 GMC Jimmy is a moderately difficult job. The switch is mounted on top of the steering column, and access requires unbolting the column and carefully lowering it. This can be an uncomfortable and awkward job, often described by DIYers as a "pain in the butt." It involves working in a tight space under the dashboard. While it doesn't require many special tools, patience is essential. It is crucial to properly align the actuator rod with the new switch during installation.
Frequently Asked Questions (FAQ)
Can I drive with a bad ignition switch?
No. A faulty ignition switch can cause the engine to stall at any time, which also causes an immediate loss of power steering and power brakes. This is a serious safety hazard that could lead to a crash.
Why do my lights flicker but the truck won't start?
This is a classic symptom of a bad ignition switch. The internal contacts that power the dashboard may be making a weak connection, while the separate, heavy-duty contacts for the starter circuit have failed completely. It can also be a sign of a weak battery or poor battery connections, so always check those first.
Is this a hard part to replace myself?
For an experienced DIYer, it is manageable. However, it requires dropping the steering column and working in an awkward position under the dash. Many find it frustrating. If you are not comfortable with this, a professional mechanic can do the job in a couple of hours.
Are there any recalls for the 1970-1980 GMC Jimmy ignition switch?
No. While GM had major ignition switch recalls in the 2010s, those were for much newer vehicles (like the Chevy Cobalt and Saturn Ion) with a completely different design and problem. Searches of the NHTSA database did not find any recalls for the ignition switch on the 1970-1980 GMC Jimmy.
Helpful Videos
Technical Specifications
OEM Part Numbers: 1116683 1116695 1116704 1116709 1116711 1116712
Located on the upper section of the steering column, activated by a mechanical actuator rod connected to the ignition lock cylinder. Available for tilt and non-tilt column configurations.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Is It the Ignition Switch or the Lock Cylinder?
- Symptoms of a Failing Ignition Switch
- Important Ordering Information
- Choosing the Right Aftermarket Ignition Switch
- Brand Quality Tiers
- New Aftermarket Ignition Switch Cost for 1970-1980 GMC Jimmy
- A Note on Installation
- Frequently Asked Questions (FAQ)
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