Q: Is an HDM headlight driver module the same as a relay switch?

asked by on August 31, 2017

GM said the problem could be the Headlight Driver Module (HDM). Is that the same as the Low Beam Relay? Do I need another Quote? Over researched problem and got myself a bit confused, you think....I guess we'll find out tomorrow. Call if you need to. Thanks Barbara

My car has 157000 miles.
My car has an automatic transmission.

Unfortunately many manufacturers will call a part by one name while call it something else. However a module is a computer and a relay is more like a switch. If they recommended a module it is likely a computer failure.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

Whining noise over 60 mph on a 2007 BMW
You went to the wrong mechanic. It's whining and it is not supposed to whine. A good mechanic can analyze it. This could've been beyond their knowledge or they don't know much about BMW. Watch my video, "how to find...
Electric power steering code C2219 is coming up on a scanner.
Hi there. The code C2219 is coming up for the computer not able to communicate with the electronic power steering unit. Check all of the wiring from the power steering unit to the computer and make sure that the wires...
EPS light
Hello. The EPS light comes on when the computer detects an issue with the vehicle's electronic power steering system. If the computer detects an issue with the system it will set off the warning light to notify the driver of...
Squeak / Grinding Sound only when moving 2013 Mercedes C250
Hi there - thanks for providing a sound sample! Noises are probably the hardest thing to diagnose, even when you can capture a recording like this. I suspect either the brake pad wear warning tab, or the driveshaft center bearing...
What causes 2010 town and country to surge at low speed and to shut off at low speeds?
Hi There, What you are describing sounds like a dirty or faulty idle air control valve (https://www.yourmechanic.com/services/idle-control-valve-replacement). The idle air control valve (https://www.yourmechanic.com/services/idle-control-valve-replacement) monitors the air intake as it is mixed with fuel prior to being injected into the engine...
2000 ford excursion v10 altinateor replaced still not charging, can drive 45 min before battery dies and truck stops running
Hello, thank you for writing in. This is going to be a process of elimination. To start, the charging system may be having issues with the battery or the alternator. Both should be tested to make sure they are working...
white smoke coming out of tailpipe after changing head gasket engine oil is very low car has tons of power
Hi there. A common problem that occurs after a head gasket is damaged is that valve guides or piston rings will also be damaged. Plus, if the engine was not fully removed and disassembled, it's likely that there is additional...
What voltage should your output sensor be at?
The speed sensor will output less than 1.5 volts since it is a voltage generator and will vary with vehicle speed. If speed output is erratic then you may have to replace the sensor and then see if readings are...
Alternator wire burnt
You may have a failing voltage regulator that could be allowing the alternator to supply too much or too little amperage to the battery resulting in the battery never maintaining a consistent charge as it is designed to. The voltage...

Related articles

The Best Used Cars to Buy for Occasional Drivers
Not Not everyone relies on their car on a daily basis. Maybe you aren’t the type that deals with a daily commute, and running from here to there constantly. If that’s the case, you may be looking for a car...
Pontiac Certified Pre-Owned (CPO) Car Program
If If you’re in the market for a used Pontiac vehicle, you may want to check out cars under their certified pre-owned program. Many manufacturers have a certified pre-owned (CPO) program, and each one is set up differently. Read on...
How to Buy a Classic Pontiac
Whether you want to buy a classic Pontiac for yourself or as a gift, here are some tips on buying one for a great value.